ArcGIS
®
9Getting Started With ArcGIS
®
Copyright © 1999–2005 ESRI
All rights reserved.
Printed in the United States of America.
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The information contained in this document is subject to change without notice.
CONTRIBUTING WRITERS
Scott Crosier, Bob Booth, Katy Dalton,Andy Mitchell, Kristin Clark
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Attribution.pmd 2/16/2005, 1:17 PM1
iii
Contents Getting to know ArcGIS
Introduction 3
1 Welcome to ArcGIS 5
What can you do with ArcGIS? 6
Unique projects to daily business 9
Tasks you perform withArcGIS 11
Tips on learningArcGIS 16
2 Exploring ArcCatalog and ArcMap 17
Introducing ArcCatalog 18
Viewing data inArcCatalog 19
Connecting to your data 20
Introducing ArcMap 24
Working with maps 25
Exploring a map 26
Adding a layer to a map 29
Adding features from a database 30
Changing how features are drawn 31
Adding labels to a map 34
Working with the map layout 36
Saving a map 42
Printing a map 43
What’s next? 44
3 Exploring GIS data 45
Geographic data models 46
Formats of feature data 50
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iv GETTING STARTED WITH ARCGIS
12
Conducting a GIS project
4 Planning a GIS project 65
What is GIS analysis? 66
The steps in a GIS project 69
Planning your project 71
5 Assembling the database 77
Organizing the project database 78
Adding data to the project folder 83
Previewing the data in ArcCatalog 88
Examining the data inArcMap 93
Cleaning up the Catalog tree 106
6 Preparing data for analysis 109
Data preparation tasks 110
What are coordinate systems? 111
Defining the coordinate system for the elevation data 113
Preparing your scripting environment 121
Projecting the river shapefile 122
Exporting the river shapefile to the geodatabase 128
Digitizing the historic park 130
Merging the parcel layers 150
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v
7 Performing the analysis 157
Setting up for analysis 158
Delineating the area the plant site should be within 159
Delineating the areas the plant site should be outside of 163
Finding the parcels that meet the location criteria 179
Finding the vacant parcels 183
Finding suitable parcels near roads and near the wastewater junction 186
Finding suitable parcels meeting the required total area 196
Reviewing the analysis results 200
8 Presenting the results 207
Designing the map 208
Setting up the map page 210
Creating the overview map 218
Creating the map of suitable parcels 224
Creating the map of highly suitable parcels 230
Creating the parcel report 242
Adding the list of site criteria to the map 245
Adding the map elements 246
Saving the map and printing it 260
What’s next? 262
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TOC.pmd 2/16/2005, 1:17 PM6
Section 1
Getting to know ArcGIS
Introduction.pmd 2/16/2005, 1:17 PM1
Introduction.pmd 2/16/2005, 1:17 PM2
3
Introduction
Welcome to Getting Started With ArcGIS. This book is intended to help
you get started using ESRI®
ArcGIS®
software and to illustrate the methods
and procedures involved in conducting a geographic information system
(GIS) project. If you are new to GIS, this book is a great place to start—
you can learn how to use a GIS to solve problems while you are learning to
use ArcGIS.
This book is divided into two sections. The first section, ‘Getting to know
ArcGIS’, discusses the basics of ArcGIS and GIS data. The second section,
‘Conducting a GIS project’, begins with Chapter 4, ‘Planning a GIS project’,
and is a sample GIS project that you can work through. The project is
designed to let you work at your own pace, without the need of additional
help. Readers who wish to complete the entire GIS project section of the
book should plan to spend about eight hours of focused time on the project.
In order to get started, you will need ArcGIS installed on a Windows®
machine. You will also need to install theArcTutor tutorial data on your
machine or on a networked drive. Proceed to Chapter 1, ‘Welcome to
ArcGIS’, when you are ready to get started.
Introduction.pmd 2/16/2005, 1:17 PM3
Introduction.pmd 2/16/2005, 1:17 PM4
IN THIS CHAPTER
5
Welcome to ArcGIS
1
• What can you do with ArcGIS?
• Unique projects to daily business
• Tasks you perform with ArcGIS
• Tips on learning ArcGIS
Welcome to ArcGIS, ESRI’s premier GIS software. You can do virtually
any GIS job at any scale of complexity with ArcGIS, from conducting a
single analysis project on your own to implementing a vast, multiuser,
enterprisewide GIS for your organization.
Use this book to learn what GIS is all about, and in just a short time you can
begin to apply ArcGIS for all of your GIS needs.
Today, GIS is used by thousands of different organizations and hundreds of
thousands of individuals to access and manage fantastically varied sets of
geographically related information.
In this chapter, you will find samples of real-world uses of ArcGIS, a brief
discussion of the different ways GIS is used, some examples of how
ArcGIS lets you use central GIS functions, and finally, some directions for
learning more about ArcGIS.
Ch01.pmd 2/16/2005, 1:17 PM5
6 GETTING STARTED WITH ARCGIS
What can you do with ArcGIS?
A wastewater department
prioritizes areas for repairs
after an earthquake.
A transit department produces
maps of bicycle paths for
commuters.
An engineering department
monitors the condition of roads
and bridges and produces
planning maps for natural
disasters.
A police department studies
crime patterns to intelligently
deploy its personnel and to
monitor the effectiveness of
neighborhood watch programs.
A water department finds
the valves to isolate a
ruptured water main.
A tax assessor’s office
produces land use maps for
appraisers and planners.
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WELCOME TO ARCGIS 7
A meteorologist issues
warnings for counties in the
path of a severe storm.
A biologist studies the impact
of construction plans on a
watershed.
A hydrologist monitors water
quality to protect public health.
An electric utility models its
circuits to minimize power loss
and to plan the placement of
new devices.
A pipeline company finds the
least-cost path for a new
pipeline.
A telecommunications
company studies the terrain to
find locations for new cell
phone towers.
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8 GETTING STARTED WITH ARCGIS
A business evaluates locations
for new retail outlets by
considering nearby
concentrations of customers.
A water resource manager
traces upstream to find the
possible sources of a
contaminant.
A police dispatcher finds the
fastest route to an emergency.
A fire fighting team predicts
the spread of a forest fire using
terrain and weather data.
An emergency management
agency plans relief facilities by
modeling demand and
accessibility.
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WELCOME TO ARCGIS 9
You can use ArcGIS in different ways, depending on the
complexity of your needs.
Some people use ArcGIS primarily as a single-user mapping
and analysis tool, usually in the context of a well-defined,
finite project. This common use of ArcGIS is sometimes
called project GIS. Other people use ArcGIS in a multiuser
system designed to serve an organization’s ongoing needs
for geographic information. Multiuser GIS is sometimes
divided into departmental and enterprise GIS according to a
system’s level of complexity and integration with the dayto-day
operation of an organization.
This book presents ArcGIS in the context of project GIS
because a project is a good, self-contained way to explore a
variety of basic GIS functions.
Project GIS
In a GIS analysis project, an analyst faces a variety of tasks
that can be grouped into four basic steps.
The first step is to convert a question, such as “Where is
the best place for a new building?” or “How many potential
customers are near this store?”, into a GIS database design
and analysis plan. This involves breaking the question into
logical parts, identifying what layers of data will be needed
to answer each part, and developing a strategy for
combining the answers to each part of the question into a
final answer.
The next step is to create a database that contains the
geographic data required to answer the question. This may
involve digitizing existing maps, obtaining and translating
electronic data from a variety of sources and formats,
making sure the layers are of adequate quality for the task,
making sure the layers are in the same coordinate system
and will overlay correctly, and adding items to the data to
track analysis result values. Personal workspaces of filebased
data and personal geodatabases are used to organize
project GIS geodatabases.
The next step is to analyze the data. This usually involves
overlaying different layers, querying attributes and feature
locations to answer each logical part of the question,
storing the answers to the logical parts of the question, and
retrieving and combining those answers to provide a
complete answer to the question.
The final step in a project-based analysis is to
communicate the results of the analysis, usually to people
who do not use GIS and who have different levels of
experience in dealing with maps. Maps, reports, and graphs
are all used, often together, to communicate the answer to
the question.
Multiuser GIS
In a multiuser GIS, people in an organization—from a few
in a single office to hundreds in different branches—use
GIS in different ways to support their daily tasks.
Departmental GIS refers to systems developed within a
single department to support a key function of the
department. For example, a planning department might
routinely use GIS to notify property owners of proposed
zoning changes near their property.
A departmental GIS is usually managed within the
department and often has specialists devoted to different
Unique projects to daily business
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10 GETTING STARTED WITH ARCGIS
tasks. For example, a department might have its own
system administrator, digitizer, and GIS analyst.
Departmental GIS is often customized to automate and
streamline procedures. For example, a planning department
could use a GIS application that finds the names and
addresses of parcel owners within a designated area and
automatically generates notification letters.
An enterprise GIS spans departments in an organization.
These large systems support multiple functions of an
organization, from daily business to strategic planning. An
enterprise GIS is usually managed as a part of the
organization’s information technology infrastructure. For
example, a city’s enterprise GIS integrates the business
functions of building and maintaining the city. The
engineering department builds the infrastructure for a
subdivision using the same geodatabase that the planning
department and assessor use to do their jobs.
An organization’s entire network becomes the platform for
an enterprise GIS. To provide access to many users, an
enterprise GIS stores data in commercial relational
database management systems (RDBMSs), such as
Oracle®
, Informix®
Dynamic Server, and
Microsoft®
SQL Server™, that have been spatially enabled
by ESRI’s ArcSDE®
(formerly SDE®
) software.
Using ArcSDE allows GIS data to be viewed and edited by
many people simultaneously. To make the most of a
networked system’s capabilities, multiple seats of key
applications, such as ArcCatalog™, ArcMap™, and
ArcToolbox™, are deployed on desktop machines across
an organization. Servers supply them with data and perform
processor-intensive tasks.
The functions of a multiuser GIS are similar to those of a
project GIS but on a larger scale and operating in a
continuous, cyclical fashion. Planning is crucial for multiuser
systems, but the rewards—including increased operational
efficiency, better allocation of scarce resources,
consistency of information, and better-informed
decisions—are tremendous.
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WELCOME TO ARCGIS 11
Whether you use GIS in a project or multiuser environment,
you can use the ArcGIS Desktop applications to do your
work.
ArcCatalog is the application for managing your spatial data
holdings and database designs and for recording and
viewing metadata. ArcMap is used for all mapping and
editing tasks, as well as for map-based analysis.
ArcToolbox is a dockable window in the ArcGIS
applications used for data conversion and geoprocessing.
Using these three applications together, you can perform
any GIS task, simple to advanced, including mapping, data
management, geographic analysis, data editing, and
geoprocessing.
ArcCatalog
ArcCatalog lets you find, preview, document, and organize
geographic data and create sophisticated geodatabases to
store that data.
ArcCatalog provides a framework for organizing large and
diverse stores of GIS data.
Different views of your data help you quickly find what you
need, whether it is in a file, personal geodatabase, or remote
RDBMS served by ArcSDE.
Tasks you perform with ArcGIS
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12 GETTING STARTED WITH ARCGIS
You can use ArcCatalog to organize folders and file-based
data when you build project databases on your computer.
You can create personal geodatabases on your computer
and use tools in ArcCatalog to create or import feature
classes and tables.
You can also view and update metadata, allowing you to
document your datasets and projects.
Ch01.pmd 2/16/2005, 1:17 PM12
WELCOME TO ARCGIS 13
ArcMap
ArcMap lets you create and interact with maps. In
ArcMap, you can view, edit, and analyze your geographic
data.
You can query your spatial data to find and understand
relationships among geographic features.
You can symbolize your data in a wide variety of ways.
Ch01.pmd 2/16/2005, 1:17 PM13
14 GETTING STARTED WITH ARCGIS
You can create charts and reports to communicate your
understanding with others.
You can lay out your maps in a what-you-see-is-what-youget
layout view.
With ArcMap, you can create maps that integrate data in a
wide variety of formats including shapefiles, coverages,
tables, computer-aided drafting (CAD) drawings, images,
grids, and triangulated irregular networks (TINs).
ArcToolbox
ArcToolbox contains many GIS tools used for
geoprocessing. It is a dockable window integrated into all
the ArcGIS Desktop applications.
Ch01.pmd 2/16/2005, 1:17 PM14
WELCOME TO ARCGIS 15
Geoprocessing tasks are accomplished through form-based
tools.
Accessing the ArcGIS Desktop applications
The ArcGIS Desktop applications can be accessed using
three software products, each providing a higher level of
functionality.
• ArcView®
provides comprehensive mapping and analysis
tools, along with simple editing and geoprocessing tools.
• ArcEditor™ includes the full functionality ofArcView,
with the addition of advanced editing capabilities.
• ArcInfo®
extends the functionality of both to include
advanced geoprocessing.
ArcToolbox for ArcView contains nearly 150 tools and
ArcEditor contains nearly 170 commonly used tools for data
conversion, analysis, and management.
ArcToolbox for ArcInfo comes with a comprehensive set of
tools—more than 250 of them, includingArcInfo
Workstation coverage geoprocessing tools.
You can use this book with ArcView, ArcEditor, or ArcInfo
since it uses functionality common to all three software
products.
For more information on ArcView, ArcEditor, and ArcInfo,
see What is ArcGIS?
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16 GETTING STARTED WITH ARCGIS
This book is intended to help you learn the basics of
ArcGIS. You can use the other books that come with
ArcGIS to supplement the information in this book and to
learn more about other tasks you can perform using
ArcGIS.
When you want quick information about how to do a
specific task, you can look it up in three handy reference
books: Using ArcCatalog, Using ArcMap, and
Geoprocessing in ArcGIS. These books are organized
around specific tasks. They provide answers in clear,
concise steps with numbered graphics. Some of the
chapters also contain background information if you want to
find out more about the concepts behind a task.
Building a Geodatabase provides a step-by-step guide to
building a geodatabase and implementing your geodatabase
design inArcGIS.
Three other books, Modeling Our World, Designing
Geodatabases, and The ESRI Guide to GIS Analysis,
present the concepts behind GIS data models and
geographic analysis.
Tips on learning ArcGIS
The Desktop Help system in ArcGIS also provides a wealth
of information on using the software. Just click the Help
button on any toolbar or dialog box. For more information,
see the Help topic ‘Getting help’.
The ‘What’s next?’ section at the end of this book lists
additional resources for learning ArcGIS and for getting
help in completing your own GIS projects.
Ch01.pmd 2/16/2005, 1:17 PM16
IN THIS CHAPTER
17
Exploring ArcCatalog and ArcMap
2
• Introducing ArcCatalog
• Viewing data in ArcCatalog
• Connecting to data
• Introducing ArcMap
• Working with maps
• Exploring a map
• Adding a layer to a map
• Adding features from a database
• Changing how features are drawn
• Adding labels to a map
• Working with the map layout
• Saving a map
• Printing a map
• What’s next?
Maps are the most commonly used tools for understanding spatial information.
Whether you do analysis or editing, produce wall maps or illustrate
reports, design GIS databases or manage them—when you work with GIS
you work with maps. ArcMap allows you to work with all of your geographic
data in maps, regardless of the format or location of the underlying
data. With ArcMap, you can assemble a map quickly from predefined
layers, or you can add data from coverages, shapefiles, geodatabases, grids,
TINs, images, and tables of coordinates or addresses.
ArcCatalog is designed to work with ArcMap. In ArcCatalog, you can
browse, organize, and document your data and easily drag and drop it onto
an existing map in ArcMap. Using the tools in ArcToolbox, you can perform
sophisticated geoprocessing operations—from a dockable window available
in all the ArcGIS Desktop applications. It has never been easier to use the
power of GIS.
In this chapter, you will create a map for a planning meeting of the
Greenvalley City council. You will use ArcCatalog to find the data and
produce the map in ArcMap.
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18 GETTING STARTED WITH ARCGIS
Introducing ArcCatalog
ArcCatalog is the tool for browsing, organizing, distributing,
and documenting an organization’s GIS data holdings.
In this exercise you work for the (fictitious) city of
Greenvalley. The city council is debating a proposal to build
additional water mains downtown. As part of the process,
the council is reviewing water use in the downtown area.
You have been asked to make a map that shows the water
mains in downtown Greenvalley and the relative water use
at each parcel downtown.
To make the map easy to read, you will add the data to a
general-purpose map of the town.
Starting ArcCatalog
1. Click the Start button on the taskbar.
2. Point to Programs to display the Programs menu.
3. Point to ArcGIS.
4. Click ArcCatalog.
ArcCatalog starts, and you see two panels in the
ArcCatalog window.
The Catalog tree on the left side of the ArcCatalog window
is for browsing and organizing your GIS data. The contents
of the current branch are displayed on the right side of the
Catalog window.
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EXPLORING ARCCATALOG AND ARCMAP 19
When you need more information about a branch of the
Catalog tree, you can use the Contents, Preview, and
Metadata tabs to view your data in many different ways.
In this example, the ArcInfo coverage “cl” contains street
centerlines. It is located on a computer’s E:\ drive in a
folder called City.
If you select a data source in the tree, you can view it in
several ways, depending on the tab that you choose. Each
tab has a toolbar associated with it that allows you to
modify how you see your data.
These are the Contents views:
Viewing data in ArcCatalog
These are the Preview views:
These are the Metadata views:
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20 GETTING STARTED WITH ARCGIS
When you start ArcCatalog for the first time, the Catalog
tree has a branch for each local hard drive. Branches for
coordinate systems, database connections, geocoding
services, Internet servers, and search results can be added
by clicking the Tools menu and clicking Options, then
checking the check boxes next to the branches you want to
add to the Catalog. You can view the contents of a branch
by double-clicking it or by clicking the plus sign beside it.
You can also create new branches in the Catalog tree to
make it easier to navigate to your data. These branches are
called connections.
Before continuing, you will need to know where the tutorial
data has been installed on your system.
Making a connection to the tutorial data
Now you will add a connection to the folder that contains
the tutorial data. This new branch in the Catalog tree will
remain until you delete it.
1. Click the Connect to Folder button.
When you click the button, a window opens that lets you
navigate to a folder on your computer or to a folder on
another computer on your network.
2. Navigate to the ArcGIS\ArcTutor\Getting_Started\
Greenvalley folder on the drive where the tutorial data is
installed. Click OK.
The new connection shows up as a branch in the
Catalog tree.
Connecting to your data
1
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EXPLORING ARCCATALOG AND ARCMAP 21
Exploring the Greenvalley folder connection
You can now look at the tutorial data that you have added.
1. Click theArcGIS\ArcTutor\Getting_Started\Greenvalley
folder to view its contents on the right side of the
ArcCatalog window.
2. Click the plus sign to expand the connection in the
Catalog tree. This branch of the tree contains a folder,
map documents, and a layer.
The Greenvalley folder has a special icon to show that it
contains GIS data. By default, ArcCatalog recognizes many
different file types as GIS data including shapefiles,
coverages, raster images, TINs, geodatabases, projection
files, and so on. It also shows all available file types,
including the metadata files with the .xml extension, by
default. If the list of recognized file types does not include a
file type that you use in GIS analysis, you can customize
ArcCatalog to recognize additional file types—for example,
text files—as GIS data.
You will turn off the option to show files with the .xml
extension to provide a less cluttered view of the ArcCatalog
tree.
1. Click the Tools menu and click Options.
2. Click the General tab and uncheck Metadata documents
in the second panel, then click OK.
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22 GETTING STARTED WITH ARCGIS
The Greenvalley map document is a general-purpose map
of the city.
The Water Use layer shows a set of parcels in Greenvalley
with a color scheme that indicates relative water use at
each parcel.
Maps and layers
Maps and layers are important ways of organizing and
displaying data inArcGIS.
Maps, such as everyday paper maps, can contain many
kinds of data. The data on a map is organized into layers,
which are drawn on the map in a particular order. Each
map contains a page layout where graphic elements, such
as legends, North arrows, scalebars, text, and other
graphics, are arranged. The layout shows the map page as
it will be printed.
Layers define how a set of geographic features will be
drawn when they are added to a map. They also act as
shortcuts to the place where the data is actually stored—
not necessarily the same place as where the layer file is
stored. In this case, both the map and the layer refer to data
that is stored in the Data folder.
If you store your geographic data in a central database, you
can create maps and layers that refer to the database. This
makes it easy to share maps and layers within an
organization and eliminates the need to make duplicate
copies of your data.
Viewing the thumbnail sketch of the Greenvalley
map
The right panel of ArcCatalog displays datasets in many
different ways. You can click an object in the left panel to
view it in the right panel. One of the views that can be
useful when you want to select a particular map is the
thumbnail view.
1. Click the Thumbnails button on the Standard toolbar.
You can see the thumbnail sketch of the map.
1
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EXPLORING ARCCATALOG AND ARCMAP 23
Launch ArcMap button
Opening the Greenvalley map
You will use the Greenvalley map to provide context for the
information that the city council wants.
1. Double-click Greenvalley in the Catalog tree.
Double-clicking a map in the Catalog tree opens the map in
ArcMap.
Sometimes you may want to start ArcMap without opening
an existing map. You can start ArcMap by clicking the
Launch ArcMap button in ArcCatalog.
You can also start ArcMap as you would any other program
on your system, whether the Catalog tree is open or not.
1
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24 GETTING STARTED WITH ARCGIS
Introducing ArcMap
ArcMap is the tool for creating, viewing, querying, editing,
composing, and publishing maps.
Most maps present several types of information about an
area at once. This map of Greenvalley contains three layers
that show public buildings, streets, and parks.
You can see the layers in this map listed in the table of
contents. Each layer has a check box that lets you turn it on
or off.
Within a layer, symbols are used to draw the features. In
this case, buildings are represented by points, streets by
lines, and parks by areas. Each layer contains two kinds of
information. The spatial information describes the location
and shape of the geographic features. The attribute
information tells you about other characteristics of the
features.
In the park layer, all the features are drawn with a single
green fill symbol. This single symbol lets you identify areas
that are parks, but it does not tell you anything about the
differences between the parks.
In the street layer, the features are drawn with different line
symbols according to the type of street that the lines
represent. This symbol scheme lets you differentiate streets
from other types of features and tells you something about
the differences between the features as well.
In the buildings layer, the features are drawn with different
point symbols. The shapes and colors of the symbols allow
you to differentiate the institutions that they represent. All
of the schools are grouped together and drawn with a
particular symbol, so you can easily differentiate schools
from the hospital or from City Hall. Each school symbol is
drawn with a different color, which lets you differentiate
Pine Elementary from Greenvalley High.
ArcMap table of contents
Point features
Line features
Area features
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EXPLORING ARCCATALOG AND ARCMAP 25
ArcMap offers many ways to interact with maps.
Exploring
Maps let you see and interpret the spatial relationships
among features. You could use the map you have just
opened to find City Hall, to identify parks near schools, or to
determine the names of the streets around the library.
Analyzing
You can create new information and find hidden patterns by
adding layers to a map. For example, if you added a layer
of demographic information to the Greenvalley map, you
might use the resulting map to define school districts or find
potential customers. If you added layers of geology and
surface slope, you might use the map to identify areas at
risk for landslides.
Presenting results
ArcMap makes it easy to lay out your maps for printing,
embedding in other documents, or electronic publishing. You
can quickly make great maps of your data. When you save
a map, all of your layout work, symbols, text, and graphics
are preserved.
ArcMap includes a vast array of tools for creating and
using maps. In the rest of this chapter, you will use some of
these tools.
Working with maps
Customizing
Maps are tools for getting a job done. You can create maps
that have exactly the tools you need to help you complete
your job quickly. You can easily customize the ArcMap
interface by adding or removing tools to or from existing
toolbars or by creating custom toolbars. You can save these
changes to the interface with a particular map or for every
map that you open.
You can also use the Visual Basic®
for Applications (VBA)
programming language included in ArcMap to create new
tools and interfaces. For example, you can create a VBA
tool to make a table of the addresses of houses in a
selected area. Once the tool is created, you can associate it
with a custom toolbar and save it with a map for anyone to
use.
Programming
You can build completely new interfaces for interacting
with your maps and create new, specialized classes of
features. ArcGIS is built using Microsoft’s Component
Object Model (COM); all of the COM components are
available to developers using a COM-compliant
programming language.
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26 GETTING STARTED WITH ARCGIS
Exploring a map
You can explore a map in several ways. The Tools toolbar
contains frequently used tools that let you navigate around
the map, find features, and get information about them.
Zooming in and getting information
If you want to see an area of the map in greater detail, you
can zoom in to the map.
1. Click the Zoom In button.
2. Drag a box around one of the parks to zoom in to it.
When you drag a box on the map after clicking the
Zoom In button, the map zooms to the new area. You
can click the Back button to jump back to the previous
map extent.
3. Click the Identify Features button and click the park.
When you click a feature with the Identify Features tool,
the Identify Results window appears. You can inspect the
attributes of the feature from this window.
If the tool finds several features where you clicked, it lists
each feature on the left side of the window. You can click
the features in this list to view their attributes on the right
side of the window.
4. Close the Identify Results window.
Zooming to the map’s full extent
If you have zoomed in to the map and want to see all of it,
you can quickly zoom out to the map’s full extent.
1. Click the Full Extent button.
Now you can see the full extent of the map. The map scale
is approximately 1:95,000 (depending on your screen setup
and the size of the ArcMap window), which you can see on
the Standard toolbar. (If the map scale is not approximately
1:95,000, change it by clicking in the text box, replacing the
text with “1:95:000”, and pressing Enter.)
1 3 1
4
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EXPLORING ARCCATALOG AND ARCMAP 27
At this scale, the building symbols are not visible. The
Maximum Visible Scale property of this layer has been set
to 1:70,000. You will change some of the properties of a
layer later in this chapter.
Finding a feature
The Find button lets you search a map for features that
match your search criteria. The area you want to map is
around the Greenvalley City Hall, so you will find City Hall
and zoom to it.
1. Click the Find button .
When you click the Find button, the Find dialog box
appears. You can search for features from a particular
layer or from all layers on the map.
2. Type “City Hall” in the Find text box. Click the In
dropdown arrow and click buildings_point. Click In
fields, then click the dropdown arrow, and click NAME.
Click Find.
City Hall appears in the list of features that the tool has
found.
3. Right-click City Hall and click Zoom to feature(s).
The map zooms to the City Hall. As the scale is now
greater than the 1:70,000 threshold, the building features
appear on the map, and you can see the blue triangle
symbol for City Hall.
4. Click Cancel to close the Find dialog box.
The map now shows some of the area that you need to map
for the city council.
When you chose Zoom to feature(s), another option on the
list was Set Bookmark. A spatial bookmark preserves a
particular map extent so that you can zoom back to it
whenever you want.
Spatial bookmarks are saved with a map, so anyone who
opens a map can quickly zoom to a particular bookmarked
area.
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28 GETTING STARTED WITH ARCGIS
Zooming to a bookmarked area
Because you use this map to provide a context for other
information, you have created some spatial bookmarks for
the areas you frequently map. Downtown Greenvalley is
one of these areas.
1. Click View and point to Bookmarks.
2. Click Downtown Greenvalley.
Now the map is zoomed to the downtown area. This map
extent and scale have been used for previous maps of
downtown Greenvalley. The map you are making will be
easy for the council members to compare with the other
maps of the downtown area.
ArcMap provides an excellent interface for interactively
exploring existing maps. You can use the tools you have just
used and others to answer questions about particular
features, to find features, and to view your maps at a
variety of scales.
You can change the information that is displayed on maps
by adding and removing layers and changing the way that
layers are displayed.
In the next part of this chapter, you will add data to your
map and change the properties of a layer.
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EXPLORING ARCCATALOG AND ARCMAP 29
Adding a layer to a map
Now that you have opened a map of Greenvalley and set
the extent to downtown, it is time to make the map you
need. The city council wants the map to include downtown
water use and the location and size of existing water mains.
You will start by adding the Water Use layer to your map.
1. Position the ArcMap and ArcCatalog windows so that
you can see both of them.
2. Click the Water Use layer in ArcCatalog and drag it onto
the map. You can click and drag any layer from the
ArcCatalog tree onto an open map in ArcMap.
The layer shows parcels drawn with a graduated color
ramp. Just as the roads and buildings were drawn with
predetermined symbols when you opened the Greenvalley
map, this layer is drawn with a particular set of symbols.
2
A layer serves as a shortcut to data. It also tells ArcMap
how the data should be drawn. You can store layers in a
place that is accessible to everyone in your organization
who needs a particular set of data; the data will be
displayed the same way for each of them.
As useful as layers are, sometimes they are not available.
Fortunately, you can add raw geographic data to a map just
as easily as you can add a layer.
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30 GETTING STARTED WITH ARCGIS
Adding features from a database
When you add features directly from a coverage, shapefile,
or database, they are all drawn with a single symbol.
Now you will add the water main features to your map.
1. Position the ArcMap and ArcCatalog windows so that
you can see both of them.
2. Click the plus sign next to the Data folder in the Catalog
tree to view the contents of the folder.
3. Click the plus sign next to GreenvalleyDB.
GreenvalleyDB is a geodatabase that contains the
remainder of the data you will be using. The data in this
geodatabase is organized in five feature datasets:
Hydrology, Parks, Public Buildings, Public Utility, and
Transportation.
4. Click the plus sign next to Public Utility.
5. Click watermains_arc and drag it onto your map.
Watermains_arc is a feature class—a collection of features
represented with the same geometry (shape). In this case,
the features are polyline shapes that represent the pipes in
the water distribution system.
Geodatabases containing feature datasets and feature
classes are how ArcGIS applications manage geographic
information. In Chapter 3, you will learn more about these
and other GIS data types.
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EXPLORING ARCCATALOG AND ARCMAP 31
Changing how features are drawn
The council wants to know the approximate sizes of the
water mains downtown, so you must assign some new
symbols to the features.
1. Right-click watermains_arc in the ArcMap table of
contents and click Properties.
The layer Properties dialog box appears. You can use this
dialog box to inspect and change a wide variety of layer
properties.
The water mains feature class includes several attributes of
the water mains. As the council wants to know the sizes of
the water mains, you will group the mains into five classes
based on their diameter attribute.
2. Click the Symbology tab on the Properties dialog box.
You can change the symbol scheme for the layer, as well as
its appearance in the table of contents, from this tab.
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32 GETTING STARTED WITH ARCGIS
3. Click Quantities. The panel changes to give you controls
for drawing with graduated colors.
4. Click Graduated symbols. The panel changes to give you
controls for drawing with graduated symbols.
4
5. Click the Value dropdown arrow and click DIAMETER.
ArcMap assigns the data to five classes using the
Natural Breaks classification (Jenks’ method).
Now the width of the line symbols indicates the diameter of
the water mains. You want the water mains to be blue, so
you will change the base symbol.
6. Click the Template button.
3
5
6
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EXPLORING ARCCATALOG AND ARCMAP 33
When you click Template, the Symbol Selector dialog box
appears. Here you can choose predefined symbols, such as
the Highway line symbol, or you can design your own
symbols.
7. Click Color. The color selector dialog box appears. You
can select one of the predefined colors from this palette
or click More Colors to mix your own colors using one
of several popular color models.
8
8. Choose a dark shade of blue and click OK.
Now all of the water mains will be drawn with dark blue
lines, with the line width representing the diameter of the
water main.
9. Click OK on the Properties dialog box to see your map
with the new line symbols.
As you have seen, ArcMap has a rich set of line symbol
selection and editing tools. These and other tools also work
with point and polygon symbols.
Once you have set the symbolization for a layer to your
satisfaction, you can preserve it for later use by saving the
map (later in this chapter) or by saving the layer as its own
layer file, such as the Water Use layer you added (see
Using ArcMap for step-by-step instructions).
7
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34 GETTING STARTED WITH ARCGIS
Adding labels to a map
The map now shows some of the street centerlines and
water mains with similar symbols. To avoid confusing a
map reader, you will add street names on the map and
change the street centerline symbol.
1. Right-click street_arc in the table of contents.
2. Click Label Features.
ArcMap adds the names of the streets to the map.
Changing the street centerline symbol
1. Right-click street_arc in the table of contents again and
click Properties.
2. Click the Symbology tab.
3. Click Features, then click Single symbol.
The street centerlines will now be drawn with a single
symbol. You will change the default line color to a light gray,
so the centerlines will be visible but unobtrusive.
4. Click the Symbol button.
3 4
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EXPLORING ARCCATALOG AND ARCMAP 35
The Symbol Selector dialog box appears.
5. Click Color. Click a light gray and click OK.
6. Click OK on the layer Properties dialog box.
Now the centerlines will be drawn in a light gray, so they
will not be confused with the water mains.
5
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36 GETTING STARTED WITH ARCGIS
Working with the map layout
All of the data you need is now on the map and has
symbols. The map that you are making for the council
meeting will be printed in color on an 8.5" x 11" sheet of
paper and distributed to each council member.
1. Click View and click Layout View.
Now you can see the map on a virtual page. The layers of
data appear in a data frame on the page. Data frames are
a way of organizing the layers you want to see together on
a map.
There is always at least one data frame on a map. This one
is called Layers; you can see its name at the top of the
ArcMap table of contents.
You can add additional data frames to a map to compare
two areas side by side or to show overviews or detailed
insets.
You can see all of the data frames on your map in Layout
view. If you switch back to Data view, you will see the
layers that are in the active data frame. The active data
frame is shown in boldface type in the table of contents.
In Layout view you can change the shape and position of
the data frame on the page; add other map elements, such
as scalebars and legends, to the map; and change the page
size and orientation.
The Layout toolbar is added to the ArcMap interface when
you choose Layout view.
Data frame
Page
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EXPLORING ARCCATALOG AND ARCMAP 37
You can use the tools on the Layout toolbar to change the
size and position of the virtual page on your screen or to
zoom in or out of the virtual page.
You can also use the Tools toolbar in Layout view to
change the extent of the layers that are shown in the data
frame.
2. Right-click the page and click Page and Print Setup.
3. Click Landscape under Paper and Page to change the
page orientation, then click OK.
Now the page is in landscape orientation.
3
2
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38 GETTING STARTED WITH ARCGIS
You will add a scalebar, North arrow, legend, and title to the
page to help the council members use the map.
First, you will make some space on the page for these other
map elements by reducing the size of the data frame.
4. Click the Select Elements button.
5. Click the data frame to select it. The data frame is now
outlined with a dashed line and has selection handles at
its corners and edges.
6. Click the center of the data frame and drag it to the
upper-left corner of the layout.
7. Point to the selection handle at the lower-right corner of
the data frame. The mouse pointer becomes a twopointed
resize arrow. Click the corner and drag it up and
to the left.
Adding a scalebar
1. On the Insert menu, click Scale Bar.
4
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EXPLORING ARCCATALOG AND ARCMAP 39
The Scale Bar Selector dialog box appears.
2. Click one of the scalebars and click OK.
3. Click the scalebar and drag it to the empty space below
the left side of the data frame.
Adding a North arrow
1. Click the Insert menu and click North Arrow.
The North Arrow Selector dialog box appears.
2. Click one of the North arrows and click OK.
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40 GETTING STARTED WITH ARCGIS
3. Click the North arrow and drag it to the empty space
below the data frame and to the right of the scalebar.
Adding a legend
1. Click the Insert menu and click Legend.
The Legend Wizard appears.
Changing Legend Wizard parameters alters the appearance
of the legend on your map. The Legend Wizard takes you
through five dialog boxes that allow you to change the
layers included in your legend, the appearance of the legend
title, the appearance of the legend frame, the size and shape
of the symbol patches used to represent line and polygon
features, and the spacing between legend items.
In this case, the default legend parameters are appropriate
for your map. However, legend parameters can be modified
at any time by right-clicking the legend in the Layout view
and choosing Properties from the menu that appears.
2. Click Next several times to step through the wizard,
accepting the default legend parameters. Click Finish
when done.
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EXPLORING ARCCATALOG AND ARCMAP 41
The legend appears on your map.
3. Click the legend and drag it to the empty space to the
right of the data frame.
You can click on the blue selection handles to resize the
legend so it fits along the right side of the page.
Adding a title
1. Click the Insert menu and click Title.
A partial title, “Greenvalley”, appears in the Layout
view.
Greenvalley is the name of the map document, but you will
need a more explanatory title on the map.
2. Click the title and type “Downtown Greenvalley Water
Mains and Water Use”. Press Enter, then click and drag
the title to the top and center it on the page.
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42 GETTING STARTED WITH ARCGIS
Saving a map
You have made a lot of changes to this map. Because you
want to keep the new map that you have created and also
keep the old template map, you will use Save As to save
this map under a new name.
1. Click File and click Save As.
2. Navigate to the Greenvalley folder.
3. Type “Downtown Water”. Click Save.
Now you are ready to print a copy of this map for the city
council.
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EXPLORING ARCCATALOG AND ARCMAP 43
Printing a map
You can easily print the maps you have composed in
ArcMap. The Layout view lets you arrange map elements,
such as data frames, scalebars, and North arrows, on the
page exactly as you want them to print.
You can print your maps using any printer on your network,
and you can choose to print using Windows®
, PostScript®
,
or ArcPress™ printer engines.
1. Click File and click Print.
The Print dialog box appears. You can change the
default printer by clicking Setup.
2. Click OK.
You are ready to take the map to the council meeting.
Close ArcMap and ArcCatalog.
3. Click File and click Exit, or simply click the Close button
(X) in the upper-right corner of the ArcMap window. Do
the same for ArcCatalog.
2
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44 GETTING STARTED WITH ARCGIS
While making your first map, you learned how to start and
use two GIS applications: ArcCatalog and ArcMap.
In the next chapter you will learn more about GIS data and
how to work with various data types. Working in the field of
GIS analysis inevitably means working with geographic data
in a variety of different formats. Understanding the
advantages and limitations of each format is an important
first step in any project and is essential to the project you
will begin in Chapter 4, ‘Planning a GIS project’.
What’s next?
Ch02.pmd 2/16/2005, 1:17 PM44
IN THIS CHAPTER
45
Exploring GIS data
3
• Geographic data models
• Formats of feature data
In Chapter 2, ‘Exploring ArcCatalog and ArcMap’, you worked with a map
and layers. The layers on a map are based on GIS data. When you added the
water mains to the map, you added data from a feature class stored in a
geodatabase. Other formats for GIS data include shapefiles, coverages, and
rasters. GIS data formats vary, but they all store spatial and attribute
information.
Much data has a spatial component that may not be immediately apparent.
For example, customer databases often include addresses. With a suitable
street dataset, these addresses can be plotted as points or geocoded.
Similarly, tables of sales figures can be linked by a query statement to a
feature class of sales territories and displayed on a map.
It is useful to understand the different GIS data types and database models
when you are conducting an analysis project. This chapter contains a brief
introduction to common types of GIS data and database models.
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46 GETTING STARTED WITH ARCGIS
ArcGIS stores and manages geographic data in a number of
formats. The three basic data models that ArcGIS uses are
vector, raster, and TIN. You can also import tabular data
into a GIS.
Vector models
One way of representing geographic phenomena is with
points, lines, and polygons. This kind of representation of
the world is generically called a vector data model. Vector
models are particularly useful for representing and storing
discrete features such as buildings, pipes, or parcel
boundaries.
Points are pairs of x,y coordinates. Lines are sets of
coordinates that define a shape. Polygons are sets of
coordinates defining boundaries that enclose areas.
Geographic data models
Coordinates are most often pairs (x,y) or triplets (x,y,z,
where z represents a value such as elevation).
The coordinate values depend on the geographic coordinate
system the data is stored in. Coordinate systems are
discussed in more detail in Chapter 6, ‘Preparing data for
analysis’.
ArcGIS stores vector data in feature classes and collections
of topologically related feature classes. The attributes
associated with the features are stored in data tables.
ArcGIS uses three different implementations of the vector
model to represent feature data: coverages, shapefiles, and
geodatabases.
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EXPLORING GIS DATA 47
Raster models
In a raster model, the world is represented as a surface
that is divided into a regular grid of cells.
The x,y coordinates of at least one corner of the raster are
known, so they can be located in geographic space.
Raster models are useful for storing and analyzing data that
is continuous across an area. Each cell contains a value that
can represent membership in a class or category, a
measurement, or an interpreted value.
Raster data includes images and grids. Images, such as an
aerial photograph, a satellite image, or a scanned map, are
often used for generating GIS data.
Grids represent derived data and are often used for analysis
and modeling. They can be created from sample points,
such as for a surface of chemical concentrations in the soil,
or based on classification of an image, such as for a land
cover grid. Grids can also be created by converting vector
data.
Grids can store continuous values, such as for an elevation
surface.
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48 GETTING STARTED WITH ARCGIS
They can also store categories, such as for vegetation
types.
Grids storing categorical information can store additional
attributes about each category. For example, a grid of
vegetation types might store—for each category—a
numeric code, the name of the vegetation type, a habitat
suitability rating for certain wildlife species, and a general
type code. This is unlike feature data, where attributes are
stored for each individual feature.
The smaller the cell size for the raster layer, the higher the
resolution and the more detailed the map. However,
because the cells form a regular grid over the whole
surface, decreasing the cell size to store higher resolution
data substantially increases the total volume of data that
must be stored.
ArcGIS can recognize and use rasters from image files in
many different file types and from grids stored in
workspaces. You can add raster datasets to a map just as
you would features, and you can inspect and organize them
with ArcCatalog.
TIN models
In a triangulated irregular network model, the world is
represented as a network of linked triangles drawn between
irregularly spaced points with x-, y-, and z-values. TINs are
an efficient way to store and analyze surfaces.
Heterogeneous surfaces that vary sharply in some areas
and less in others can be modeled more accurately, in a
given volume of data, with a triangulated surface than with
a raster. That is because many points can be placed where
the surface is highly variable, and fewer points can be
placed where the surface is less variable. ArcGIS stores
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EXPLORING GIS DATA 49
triangulated surfaces as TIN datasets. As with rasters, you
can add TIN datasets to a map in ArcMap and manage them
with ArcCatalog.
For more information about raster data and TINs, see
Modeling Our World: The ESRI Guide to Geodatabase
Design.
Tabular data
You can think of a GIS as a database that understands
geometry. As with other databases, ArcGIS lets you link
tables of data together. Almost any table of data can be
joined to an existing feature class or raster dataset if they
share an attribute. For example, you may have a shapefile
of census tracts with a tract number field and a tabular file
of additional census data also containing a tract number
field. You can link the census data to the shapefile’s
attribute table and map the additional data.
Geolocating is another means of putting tabular data on a
map. Perhaps the simplest example of geolocating is
plotting points based on tables of geographic coordinates.
For example, you can plot the locations of soil samples
based on latitude–longitude values obtained from a global
positioning system (GPS) receiver. You can also plot points
by geolocating tables of addresses on an existing street
network. This is often called address geocoding.
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50 GETTING STARTED WITH ARCGIS
ArcGIS supports both file-based feature models and
database management system (DBMS) feature models.
The two file-based models are coverages and shapefiles.
Coverages and shapefiles employ a georelational data
model. They store the vector data for the features in binary
files and use unique identifiers to link features to attributes
stored in feature attribute tables in other files.
The DBMS feature model supported by ArcGIS is the
geodatabase data model. In this model, features are stored
as rows in a relational database table. The rows in the table
contain both the coordinates and the attribute information
for the features.
Coverages
Coverages are the traditional format for complex
geoprocessing, building high-quality geographic datasets,
and sophisticated spatial analysis.
Coverages contain primary, composite, and secondary
feature types. The primary features in coverages are label
points, arcs, and polygons. The composite features—routes/
sections and regions—are built from these primary feature
types.
Coverages may also contain secondary features: tics, links,
and annotation. Tics and links do not represent geographic
objects but are used to manage coverages. Annotation is
used to provide text about geographic features on maps.
Formats of feature data
Primary features in coverages
Label points can represent individual point features, for
example, wells. In the diagram below, the point in the
upper left represents well number 57.
Label points also link attributes to polygons. Each polygon in
a coverage has a single label point with its feature ID
number, usually located near the polygon’s center. The
diagram below shows the label points of polygons 102 and
103.
58
59
57
102
103
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EXPLORING GIS DATA 51
Arcs are connected sets of line segments, with nodes at the
endpoints. A single arc can stand alone, such as a fault line
on a geologic map; several arcs can be organized into line
networks, such as stream or utility networks.
Arcs can also be organized into polygons that represent
areas, such as soil types.
Nodes are the endpoints of and connections between arcs.
Nodes can have attributes, so they can represent point
features in a network, such as valves in a network of water
mains.
Nodes are important for tracking how features in coverages
are connected to each other; this is called topology. You’ll
learn more about coverage topology later in this section.
Polygons represent areas. They are bounded by arcs,
including arcs that define island polygons. Polygons in a
coverage may share arcs such as B and C below, but they
do not overlap. Each point in an area falls within exactly
one polygon so, for example, a point within polygonAis
outside of polygon B.
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52 GETTING STARTED WITH ARCGIS
Composite features in coverages
Routes and sections are linear features that are composed
of arcs and parts of arcs. Routes define paths along an
existing linear network such as the route from a house to an
airport along a street network.
Because points of interest on a network are not always at
nodes, sections identify partial arcs. They record how far
along a given arc a route begins or ends.
Regions are area features that are composed of polygons.
Unlike polygons, regions can be discontinuous. For example,
the mainland and an island can be mapped as two polygons,
but they can belong to the same region.
In the diagram above, polygons A and D belong to
region R1.
Regions in a coverage can also overlap. For example, in a
coverage of forest polygons, two regions that represent
different forest fires could overlap if an area that burned in
one year also burned in another.
In the diagram above, region R2 and region R3 share
polygon C.
Secondary features in coverages
Annotation features are text strings that describe a feature
when a map is displayed or printed. Annotation can be
positioned at a point, between two points, or along a series
of points. Annotation is used to make maps easier to read
and understand.
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EXPLORING GIS DATA 53
Annotation is stored in geographic coordinates, so it
maintains its position and scale relative to the other
coverage features when displayed.
Tics are geographic control points. They represent known
locations on the ground and are used to register and
transform the coordinates of a coverage.
Tics allow features digitized from a paper map to be
accurately transformed from digitizer units, such as
centimeters or inches, to real-world units, such as
kilometers or miles. It is good practice to use the same tic
locations when you digitize sets of features from a map into
different coverages so they will overlay correctly.
Links are displacement vectors that are used to adjust the
shape of coverages, for example, to match the edges of
adjacent coverages. Links consist of a from-point and a
to-point.
Coverage topology
Topology is the procedure for explicitly defining and using
the spatial relationships inherent in feature geometry. The
three major topological relationships that coverages
maintain are connectivity, area definition, and contiguity.
Coverages implement topology and explicitly record these
spatial relationships in special files. Storing connectivity
makes coverages useful for modeling and tracing flows in
linear networks. Storing information about area definition
and contiguity makes it possible to find or merge adjacent
polygons and to combine geographic features from
different coverages with overlay operations.
Coverages store connectivity by recording the nodes that
mark the endpoints of arcs. Arcs that share a node are
connected. This is called arc–node topology. Each arc is a
connected set of vertices with a from-node and a to-node.
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54 GETTING STARTED WITH ARCGIS
The illustration below shows three arcs labeled 1, 2, and 3.
Arc 1 starts from node 10 and goes to node 20. Its shape is
defined by vertices a, b, c, and d. Arc 2 is connected to
arc 1 at nodes 10 and 20.
Coverages define areas by keeping a list of connected arcs
that form the boundaries of each polygon. This is called
polygon–arc topology.
In this illustration polygonA is defined by arcs 1 and 2.
Coverages store contiguity by keeping a list of the
polygons on the left and right side of each arc. This is called
left–right topology. Polygons that share an arc are
contiguous. In this illustration polygons A and B are
contiguous because A is to the left of arc 2 and B is to the
right.
Storage of coverages
Coverages are stored in workspaces. A workspace is a
folder in the file system. The workspace folder contains a
folder named info and folders named for each coverage in
the workspace.
Here, the workspace is called a_workspace, and the
coverages are called a_coverage and b_coverage.
A coverage folder contains a set of files that store
information about the features in the coverage—
coordinates, topology, and so on. The attributes of coverage
features are stored in feature attribute tables that are
Polygon
1
2
3
BA
1
2
3
BA Shared arc
Workspace in the file system
10
a
b
c d k
e
f
g
h
i
j
20
1
2
3
Shared node
Arc
Vertex
Ch03.pmd 2/18/2005, 8:52 AM54
EXPLORING GIS DATA 55
managed by an INFO™ database. The info folder contains
INFO data files and table definitions for each coverage.
In ArcCatalog, you see a coverage workspace as a GIS
data folder. You can identify the geometry of a coverage—
point, line, polygon, and so on—by its icon. You can also see
the feature classes within a coverage.
Here, you can see that a_workspace contains two
coverages: a_coverage and b_coverage. The a_coverage
contains an arc feature class and a tic feature class. This
coverage has polygon topology, so it contains a polygon
feature class and a label feature class as well. The dataset
b_coverage is a line coverage, so it just contains arc and tic
feature classes.
You may also see additional data tables in a coverage
workspace if there are other tables stored in the INFO
database, such as linked data tables or symbol lookup
tables.
Shapefiles
Shapefiles are useful for mapmaking and some kinds of
analysis. A great deal of geographic data is available in
shapefile format.
Shapefiles are simpler than coverages because they do not
store full topological associations among different features
and feature classes. Each shapefile stores features
belonging to a single feature class.
Features in shapefiles
Shapefiles have two types of point features: points and
multipoints. They have line features that can be simple lines
or multipart polylines. They also have area features that are
simple or multipart areas called polygons.
Point shapes are simply single-point features, such as wells
or monuments. Here, well number 57 is selected.
Workspace in ArcCatalog
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56 GETTING STARTED WITH ARCGIS
Multipoint shapes are collections of points that all
represent one feature. A group of small islands could be
represented as a single multipoint shape. Here, multipoint
feature 22 is selected.
Line shapes can be simple continuous lines, such as a fault
line on a map. They can also be polylines that branch, such
as a river. Line shapes can also have discontinuous parts.
Polygon shapes can be simple areas, such as a single
island. They can also be multipart areas, such as several
islands that constitute a single state.
Polygon shapes can overlap, but the shapefile does not
store topological relationships between them. The market
areas of two stores could be represented as overlapping
polygon shapes.
Storage of shapefiles
Shapefiles are stored in folders. A shapefile consists of a
set of files of vector data in the shapefile and a dBASE®
.dbf file containing the attributes of the features. Each
constituent file shares the shapefile name.
22
33
Constituent files of a line
shapefile
Folder with a shapefile
in the file system
Ch03.pmd 2/16/2005, 1:17 PM56
EXPLORING GIS DATA 57
In addition to generic features, such as points, lines, and
areas, you can create custom features, such as
transformers, pipes, and parcels. Custom features can have
special behavior to better represent real-world objects. You
can use this behavior to support sophisticated modeling of
networks, data entry error prevention, custom rendering of
features, and custom forms for inspecting or entering
attributes of features.
Features in geodatabases
Because you can create your own custom objects, the
number of potential feature classes is unlimited. The basic
geometries (shapes) for geodatabase feature classes are
points, multipoints, network junctions, lines, network
edges, and polygons. You can also create features with new
geometries.
All point, line, and polygon feature classes can:
• Be multipart—for example, multipoint shapes or regions
in a coverage
• Have x,y; x,y,z; or x,y,z,m coordinates—m-coordinates
store distance measurement values, such as the distance
to each milepost along a highway
• Be stored as continuous layers instead of tiled
A shapefile contains shapes of only one geometry: point,
multipoint, line, or polygon.
When you look at a folder of shapefiles in ArcCatalog, you
see the shapefiles as standalone feature classes.
Geodatabases
Geodatabases implement an object-based GIS data model—
the geodatabase data model. A geodatabase stores each
feature as a row in a table. The vector shape of the feature
is stored in the table’s shape field, with the feature
attributes in other fields. Each table stores a feature class.
In addition to features, geodatabases can also store rasters,
data tables, and references to other tables. Geodatabases
are repositories that can hold all of your spatial data in one
location. They are similar to adding coverages, shapefiles,
and rasters into a DBMS. However, they also add
important new capabilities lacking in file-based data models.
Some advantages of a geodatabase are that features in
geodatabases can have built-in behavior; geodatabase
features are completely stored in a single database; and
large geodatabase feature classes can be stored seamlessly,
not tiled.
Folder in ArcCatalog
Shapefiles in ArcCatalog
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58 GETTING STARTED WITH ARCGIS
Point and multipoint geodatabase features are similar to
the corresponding feature types in shapefiles.
Generic point features could, for example, represent
building locations in a city.
Custom point features could also represent buildings, but
they might include an interface that would list the owner,
area, and assessed value of the building or display a
photograph or schematic of the building.
Network junction features are points that play a topological
role in a network, somewhat like nodes in a coverage.
There are simple and complex network junction features.
A simple junction feature might be used to represent a
fitting that connects two pipes. It could have validation
behavior that would ensure that connected pipes are of the
correct diameter and materials.
A complex junction feature plays a more complex role in a
network. It can contain internal parts that play a logical and
topological role in the larger network.
For example, a complex junction feature could be used to
represent a switch in an electric power network. In one
position the switch could connect pointA to point B, while in
another position it could connect pointA to point C.
The switch might have editing validation rules that would
control the types of power lines that could be connected to
it. It could also have custom behavior that would draw the
switch with different symbols depending on its state—open
or closed, for example.
Line features are lines built from three kinds of segments:
line segments, circular arcs, and Bézier splines.A single line
could be built from all three parts, as in the illustration on
the right, below.
Ch03.pmd 2/16/2005, 1:17 PM58
EXPLORING GIS DATA 59
A
B
Lines can be used to represent linear geographic features,
such as roads or contour lines. Line features can have
custom drawing behavior that generalizes the line
depending on the map scale or that controls the placement
of annotation along the line.
Network edge features are lines that play a topological role
in a network. They can be used for tracing and flow
analysis.
Here, the network between A and B has been traced. The
network contains simple and complex network edge
features.
A simple edge feature is a linear network feature that
connects to junction features at its endpoints. In this
respect, simple edge features are similar to arcs, which
have nodes at their endpoints. A simple edge feature could
be used to represent a pipe in a water network.
Simple edge features can have connectivity rules; for
instance, a 10-cm pipe must connect to a 10-cm fitting.
They can also have special class methods, so a pipe feature
could calculate the pressure drop of a liquid flowing from
one end to another based on the pipe diameter, roughness,
and length. They can have special query, editing, and data
entry interfaces.
A complex edge feature is a linear network feature that
can support one or more junctions along its length, yet
remain a single feature. In the example below, the line from
A to B is a single complex edge feature.
A power line could be represented as a complex edge
feature. It could have junction features at its ends and
additional junctions where other lines attach to it along its
length. As with simple edge features, complex edge
features can have special class methods and interfaces.
A
B
Ch03.pmd 2/16/2005, 1:17 PM59
60 GETTING STARTED WITH ARCGIS
Polygon features represent areas. Their boundaries can be
composed of line, circular arc, and Bézier spline
segments—the same geometries used to create line
features. They can be simple closed shapes, or they can
have discontinuous parts. Polygon features can also have
nested islands and lakes.
You can use polygon features to represent geographic
features, such as buildings, census blocks, or forest stands.
As with other geodatabase features, polygon features can
have customized behavior and interfaces. A custom
building polygon could be drawn as a plan view at one
scale, as a generalized building footprint at another, and
with a point symbol at another. It could also have a custom
interface for editing and viewing its attributes.
You can create your own custom geodatabases from
scratch, or you can modify elements of an existing
geodatabase. For more information about designing
geodatabases and creating custom features, see Modeling
Our World: The ESRI Guide to Geodatabase Design and
Building a Geodatabase.
Topology in a geodatabase
Topology in a geodatabase allows you to represent shared
geometry between features within a feature class and
between different feature classes. You can organize the
features in a geodatabase to create planar topologies or
geometric networks.
Feature classes can share geometry with other feature
classes in a planar topology. For example, you might define
a topological relationship between streets, blocks, block
groups, and census tracts. The street segments define the
boundary of the block they enclose. Groups of blocks can
be collected into block groups, and block groups into tracts.
A planar topology is composed of a set of nodes, edges,
and faces. When you update the boundary of one feature,
the shared boundaries are updated as well.
Ch03.pmd 2/16/2005, 1:17 PM60
EXPLORING GIS DATA 61
Topologically related edge and junction features within a
dataset can be bound into a geometric network. This is
useful when the features must be connected to each other
with no gaps. For example, you could organize pipes,
valves, pumps, and feeders into a water network.
Storage of geodatabase features
Geodatabase features reside in geodatabases. A multiuser,
versioned geodatabase can be implemented using ArcSDE
software in any of the leading commercial all-relational
databases. Single-user, or personal, geodatabases are
implemented in a Microsoft Access .mdb file.
You access the database through ArcGIS applications
including ArcMap andArcCatalog.
Geodatabase feature classes each contain one geometric
feature type. Related feature classes can be organized into
feature datasets. Feature datasets are useful for organizing
feature classes with a shared topology. They can also be
used to organize feature classes thematically. For example,
you might have three feature classes in a waterbodies
feature dataset: points, representing ponds; lines,
representing rivers; and polygons, representing lakes.
When you look at a geodatabase in ArcCatalog, you see the
database tables as collections of feature datasets and
feature classes, or simply as standalone feature classes.
Geodatabase feature classes are stored with spatial
indexes, so you can work efficiently with small areas of
large seamless databases. This eliminates the need to divide
large, complex datasets into separate tiles.
Getting more information
There are many facets to each vector data format, and
there are many issues to consider when choosing one over
another within a specific database design. For a full
discussion of these issues, see Modeling Our World: The
ESRI Guide to Geodatabase Design and Building a
Geodatabase.
Folder with geodatabase in the file system
Database files
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Ch03.pmd 2/16/2005, 1:17 PM62
Section 2
Conducting a GIS project
section2.pmd 2/16/2005, 1:17 PM63
section2.pmd 2/16/2005, 1:17 PM64
IN THIS CHAPTER
65
Planning a GIS project
4
• What is GIS analysis?
• The steps in a GIS project
• Planning your project
Beginning with this chapter and through the rest of the book, you will
conduct a sample GIS analysis project. The tasks you perform will help you
learn the methods for performing your own GIS projects. You’ll learn about
several specific GIS analysis techniques and, perhaps more important, you’ll
learn how to plan and carry out a GIS project.
This chapter provides an overview of GIS analysis and presents the steps
involved in conducting a GIS project. It then walks you through the first
step—planning the project.
The scenario for the project involves finding the best site for a new
wastewater treatment plant for the fictitious city of Greenvalley. To find a
suitable site you will need to know the site selection criteria. You’ll then
need to identify the data needed to address these criteria and use the data to
find suitable sites for the plant. These are fundamental elements of a GIS
analysis project.
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66 GETTING STARTED WITH ARCGIS
What is GIS analysis?
The phrase “GIS analysis” encompasses a wide variety of
operations that you can do with a geographic information
system. These range from simple display of features to
complex, multistep analytical models.
Showing the geographic distribution of data
Perhaps the simplest form of GIS analysis is presenting the
geographic distribution of data. This is conceptually the
same as sticking pins in a wall map, a simple but powerful
method of detecting patterns.
Here, the map is the analysis. A police department might
analyze burglary patterns by plotting the addresses of
reported break-ins. The department could make the map
more informative by displaying the incidents with different
symbols to show the time of day, method of entry, or types
of valuables reported stolen.
Querying GIS data
Another type of GIS analysis is querying, or selecting from,
the database. Queries let you identify and focus on a
specific set of features. There are two types of GIS queries,
attribute and location queries.
Attribute queries, or aspatial queries, find features based on
their attributes. The police department mentioned above
could use an attribute query of its database to obtain a table
of crimes that fall into a particular category.
Here are the results from a query on the CRIM_CAT field,
showing records where the value in the field is 9. The map
shows the results of the query.
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PLANNING A GIS PROJECT 67
Location queries, or spatial queries, find features based on
where they are. The police department could use a location
query of the database to find crimes that occurred within a
given area.
One way to do a location query is by drawing a rectangle
on the map. Here, the police department has selected only
those crimes that occurred within the rectangle. These
crimes could be studied together to determine if any of
them are related.
The police department could also do more complex spatial
queries using polygon features, such as census tracts,
selected from another layer. One of the most useful
features of a GIS is that you can see the results of both
spatial and aspatial queries on the map.
Identifying what’s nearby
A third type of GIS analysis is finding what is near a
feature. One way to find what is near a feature is by
creating a buffer around the feature.
A city planning commission could identify the area within
1,000 meters of a proposed airport by buffering the airport
feature. The buffer could be used with other layers of data
to show which schools or hospitals would be near the new
airport.
A powerful function of GIS analysis is that the output of
one procedure can be used in another. Here, the buffer
around the airport is used in a location query. Two schools
and a hospital that are within the buffer have been selected.
The school that is outside the buffer was not selected.
Ch04.pmd 2/16/2005, 1:17 PM67
68 GETTING STARTED WITH ARCGIS
Overlaying different layers
A fourth type of GIS analysis is overlaying different layers
of features. You can create new information when you
overlay one set of features with another. There are several
types of overlay operations, but all involve joining two
existing sets of features into a single new set of features.
For example, a farmer wants to find how much land can be
planted with a new crop. The crop can’t be planted on
hillsides and needs soils that are highly permeable.
The farmer combines, in a union overlay, two existing
layers of data about the farm: polygons of the ground
surface classified by slope and polygons of soil permeability.
The farmer can now select the new polygons that have low
slopes and high permeability.
There are several different spatial overlay and spatial
manipulation operations that you can use on layers including
union, intersect, merge, dissolve, and clip.
Doing a complex analysis
You can combine all of these techniques and many others in
a complex GIS analysis. With a GIS you can create detailed
models of the world to solve complicated problems.
Because a GIS can perform these operations rapidly, it is
possible to repeat an analysis using slightly different
parameters each time and compare the results. This can
allow you to refine your analysis techniques.
This section has provided a brief overview of some of the
common types of GIS analysis. For more information on
these and other kinds of analysis you can perform using
GIS, see The ESRI Guide to GIS Analysis.
In the next section you’ll learn about the steps in a typical
GIS analysis project.
Slope Permeability Slope and
permeability
Ch04.pmd 2/16/2005, 1:17 PM68
PLANNING A GIS PROJECT 69
The steps in a GIS project
In a typical GIS analysis project, you identify the
objectives of the project, create a project database
containing the data you need to solve the problem, use GIS
functions to create an analytical model to solve the
problem, and present the results of the analysis.
Step 1: Identify your objectives
The first step of the process is to identify the objective of
the analysis. You should consider the following questions
when you are identifying your objectives:
• What is the problem to solve? How is it solved now?
Are there alternate ways to solve it using a GIS?
• What are the final products of the project—reports,
working maps, presentation-quality maps?
• Who is the intended audience of these products—the
public, technicians, planners, officials?
• Will the data be used for other purposes? What are the
requirements for these?
This step is important because the answers to these
questions determine the scope of the project as well as how
you implement the analysis.
Step 2: Create a project database
The second step is to create a project database. Creating
the project database is a three-step process. The steps are
designing the database, automating and gathering data for
the database, and managing the database.
Designing the database includes identifying the spatial data
you will need based on the requirements of the analysis,
determining the required feature attributes, setting the
study area boundary, and choosing the coordinate system to
use.
Automating the data involves digitizing or converting data
from other systems and formats into a usable format, as
well as verifying the data and correcting errors.
Managing the database involves verifying coordinate
systems and joining adjacent layers.
Creating the project database is a critical and timeconsuming
part of the project. The completeness and
accuracy of the data you use in your analysis determines
the accuracy of the results.
Step 3: Analyze the data
The third step is to analyze the data. As you’ve seen,
analyzing data in a GIS ranges from simple mapping to
creating complex spatial models. A model is a
representation of reality used to simulate a process, predict
an outcome, or analyze a problem.
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70 GETTING STARTED WITH ARCGIS
A spatial model involves applying one to three categories of
GIS functionality to some spatial data. These functions are:
• Geometric modeling functions—calculating distances,
generating buffers, and calculating areas and perimeters
• Coincidence modeling functions—overlaying datasets to
find places where values coincide
• Adjacency modeling functions—allocating, pathfinding,
and redistricting
With a GIS you can quickly perform analyses that would be
impossible or extremely time-consuming if done by hand.
You create alternative scenarios by changing your methods
or parameters and running the analysis again.
Step 4: Present the results
The fourth step is to present the results of your analysis.
Your final product should effectively communicate your
findings to your audience. In most cases, the results of a
GIS analysis can best be shown on a map.
Charts and reports of selected data are two other ways of
presenting your results. You can print charts and reports
separately, embed them in documents created by other
applications, or place them on your map.
What’s next?
Now that you have reviewed the steps in a GIS project, you
are ready to begin planning your own project. The next
section presents an overview of the steps for the
Greenvalley wastewater treatment plant project. The first
step—identifying the project objectives—is covered in this
chapter. The rest of the steps comprise the remaining
chapters in this book.
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PLANNING A GIS PROJECT 71
Planning your project
Planning is a critical step in any GIS project and can save
you time and effort once you get to the database creation,
analysis, and mapping steps. During the planning phase
you identify the project objectives, define the criteria for
the analysis, and identify the data required to support the
analysis. You should also consider the approach you’ll use
for the analysis and what the final products of the project
will be. Once you’ve done this, you can proceed to create
the project database.
Throughout the rest of this book you will be working on a
small GIS analysis project. In the process, you’ll learn how
to plan a GIS project and how to use ArcMap and
ArcCatalog together to carry it out. While you’ll be
performing a specific type of analysis—finding a site for a
new facility—the steps you’ll follow in the project, and
many of the specific tasks, will be applicable to a range of
GIS projects. The scenario for the project is to find a
suitable site for a new wastewater treatment plant.
The city of Greenvalley is growing. To support this growth,
the city is building a new wastewater treatment and
recycling plant. The city plans to use conservation and
wastewater recycling to help meet its expected water needs.
The diagram to the right outlines the steps in a GIS project
and shows where each step is covered in the remaining
chapters in this book.
In this chapter, you’ll carry out step 1—identifying the
project objectives. You’ll also do some planning for the
remaining steps.
Steps in a GIS project
Step 1: Identify the project objectives—Chapter 4
Step 2: Create the project database
Assemble the data—
Chapter 5
Prepare the data for
analysis—Chapter 6
Step 3: Analyze the data—Chapter 7
Step 4: Present the results—Chapter 8
CRITERIA DATA SET ATTRIBUTES
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72 GETTING STARTED WITH ARCGIS
Step 1: Identify the project objectives
The objective of this GIS analysis is to find a suitable site
for the city’s new wastewater treatment plant. The city has
never used a GIS model to site a wastewater treatment
plant. The existing plant was sited many years ago using a
quadrangle map, acetate overlays, and the city council’s
knowledge of the area in consultation with the city engineer.
This approach was adequate but time-consuming, and the
public was not involved in the process.
The problem has become more difficult as the area has
become more developed and environmental and public
health regulations more stringent. The council has chosen to
use a GIS model in order to speed the process and to
ensure that the necessary regulations are complied with.
Because the council recognizes that siting such a plant can
be controversial, it wants the analysis to identify all of the
parcels that could be used for the plant site, then identify
the highly suitable parcels, based on specific criteria. The
possible sites will be discussed at a public meeting. The
map you create for the meeting should make clear which
parcels are highly suitable, which are less suitable, and
which are unsuitable.
The city has provided you with a list of the criteria for a
suitable site. The parcels chosen for the site must be:
• Below 365 meters in elevation, to minimize pumping
costs
• Outside the floodplain, to avoid spillage during storms
• Within 1,000 meters of the river, to minimize pipeline
construction for treated water that is discharged
• At least 150 meters from residential property and parks,
to minimize the impact on the city’s residents
• On vacant land that can be developed, to minimize land
acquisition and construction costs
In addition, to further reduce construction costs, the city
would prefer that the site be:
• Within 1,000 meters of the main wastewater junction
(within 500 meters is considered even more suitable)
• Within 50 meters of an existing road
The plant will also require a total of at least 150,000 square
meters in area.
A preliminary review of existing paper maps has shown
that the most likely location for the plant is in the
northwest corner of the city, near the river, and in a lowlying
area. This will be the study area for the project. The
GIS analysis will allow you to combine the criteria to
identify specific parcels that are suitable sites.
Step 2: Create the project database
Creating the database for this project will be a two-step
process. First you’ll assemble the existing data and review
it. Then you’ll prepare the data for analysis. Some of the
data will be usable as is; other layers will need additional
processing. You may also need to automate some data.
You’ll assemble the data in Chapter 5, ‘Assembling the
database’, and prepare the data for analysis in Chapter 6,
‘Preparing data for analysis’. At this point, though, you can
plan for those tasks by identifying the data layers you’ll
need and the sources of the data.
Assemble the project data
Several city of Greenvalley departments maintain GIS data
and have working arrangements to share data for city
projects. Some of this data is already stored in the city’s
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PLANNING A GIS PROJECT 73
GreenvalleyDB database. The city also has data sharing
agreements with several regional and state agencies.
Because a database containing much of the data you need
already exists, you will not need to spend as much time on
designing and automating your project database as you
would otherwise. However, you will still need to do some
database design work for your project database. You’ll
need to identify the dataset and any attributes required for
each criteria. You’ll then research the available data to see
which layers will meet your needs.
Each of the city’s criteria will require a layer of data for the
analysis. Here is a list of the criteria and the corresponding
datasets and attributes.
Note that the parcels dataset will be used for several
criteria.
You can now take inventory of the data that you have and
see which layers correspond to the required datasets. You
can also identify other layers that you need to obtain or
create.
To find areas below 365 meters elevation, you need a
source of elevation data. A colleague at the State
Department of Transportation (DOT) has provided an
elevation grid. Because you simply need to know whether
or not a parcel is below 365 meters, you will use a polygon
of areas below 365 meters, which your colleague at DOT
has created from the grid. This data is in a shapefile format.
To find parcels outside of the floodplain, you will use the
City Planning Department’s digital flood zone layer, stored
as a feature class in the city’s GreenvalleyDB geodatabase.
To identify areas within 1,000 meters of the river, you will
first need a layer of the river. The County Water Resources
Department has a shapefile of the river.
You will need a dataset of the parcels in your study area.
The city tax assessor has a tiled database of parcels stored
as shapefiles. Two of these tiles cover your study area. The
parcel database includes a land use attribute that you will
use to identify residential parcels—so you can buffer them
to 150 meters—and vacant parcels. You will use the area
attribute of the parcel shapefile to identify possible sites
with an area of at least 150,000 square meters.
To find areas more than 150 meters from parks, you’ll need
a parks layer. The City Parks and Recreation Department
has a feature class of existing parks, which is stored in the
GreenvalleyDB geodatabase.
CRITERIA DATASET ATTRIBUTES
LESS THAN 563 METERS ELEVATION ELEVATION ELEVATION IN METERS
OUTSIDE THE FLOODPLAIN FLOODPLAIN N/A
WITHIN 000,1 METERS OF THE RIVER RIVER N/A
AT LEAST 051 METERS FROM
RESIDENTIAL PROPERTY
PARCELS LAND USE
AT LEAST 051 METERS FROM PARKS PARKS N/A
ON VACANT LAND PARCELS LAND USE
WITHIN 000,1 METERS OF THE
WASTEWATER JUNCTION
WASTEWATER
JUNCTION
N/A
WITHIN 05 METERS OF A ROAD ROADS N/A
AT LEAST 000,051 SQ. METERS PARCELS AREA IN SQUARE METERS
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74 GETTING STARTED WITH ARCGIS
There is also a recently discovered historic site in the
project study area. The city plans to develop a park around
the site, but the proposed park boundary has not been
placed into the park feature class yet. You will get this
information into your project database by digitizing from a
scanned image of the draft park boundary map.
To find parcels within 1,000 meters of the main wastewater
junction, you will need a layer that includes the junction.
The City Utility Department has a coverage of the
wastewater mains and the junction.
To identify parcels that are within 50 meters of a road, you
will use the existing streets feature class from the
GreenvalleyDB geodatabase.
The table below lists the layers you’ll assemble for the
project database, based on the available data. The source
and the format of each layer are also listed.
The database will also include the scanned image of the
historic park, which you’ll use to digitize the new park.
You’ll also include the elevation grid, as you may want to
display it on your final map.
In Chapter 5, ‘Assembling the database’, you’ll assemble
the data and organize it so it’s easily accessible within a
single project folder. You’ll then review the data to see
which layers will require additional processing.
Prepare the data for analysis
Based on your review of the data, you’ll determine which
layers are currently usable and which require additional
processing for use in the analysis. Some of the common
tasks involved in preparing data for analysis include:
• Checking data quality—making sure the data is accurate
and up-to-date
• Converting data between formats
• Automating data by digitizing, scanning, converting, or
geolocating
• Defining coordinate systems
• Projecting layers to a new coordinate system
• Merging adjacent layers
You’ll need to perform some of these tasks for your project
database. You already know, for instance, that the boundary
of the proposed park surrounding the historic site will need
to be digitized. You have a scanned map of the proposed
boundary that you will register to the city’s geodatabase and
digitize using the parcels layer as a backdrop. The new park
feature will be added to the existing park feature class in
the GreenvalleyDB geodatabase.
LAYER SOURCE FORMAT
ELEVATION STATE DEPT. OF TRANSPORTATION GRID
ELEVATION < 563 M STATE DEPT. OF TRANSPORTATION SHAPEFILE
FLOODPLAIN CITY PLANNING DEPT. GEODATABASE
RIVER COUNTY WATER RESOURCES DEPT. SHAPEFILE
PARCELS CITY TAX ASSESSOR SHAPEFILES (TILED)
PARKS CITY PARKS AND RECREATION DEPT. GEODATABASE
HISTORIC PARK CITY PARKS AND RECREATION DEPT. SCANNED IMAGE
WASTEWATER JUNCTION CITY UTILITIES DEPT. COVERAGE
STREETS CITY STREETS DEPT. GEODATABASE
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PLANNING A GIS PROJECT 75
You will also need to merge the two parcel tiles for your
study area to make the analysis easier to perform.
Once you’ve reviewed the existing data, in Chapter 5,
‘Assembling the database’, you’ll be able to see which
other layers require additional processing.
Most of the data for the project is already in coverage,
shapefile, geodatabase, or raster format, all of which
ArcGIS can use, simultaneously. There may be cases,
though, where you’ll need to convert data to a different
format—for example, if converting from vector to raster
format or from shapefile to geodatabase feature class, for
storage in an existing geodatabase.
ArcGIS can display and overlay layers in different
coordinate systems as long as the coordinate system for
each layer is defined. You’ll need to check this, especially
for data you’ve obtained from other sources.
You’ll perform the necessary data processing tasks in
Chapter 6, ‘Preparing data for analysis’.
Step 3: Analyze the data
During the planning stage of the project, you’ll want to
consider the analysis methodology and list the major steps
in the process. That way you can make sure you are aware
of all the datasets you will need and can include them as
you create the project database. You may want to create a
schematic diagram of the process as a guide.
The diagram to the right shows the process for the
wastewater treatment plant siting analysis.
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76 GETTING STARTED WITH ARCGIS
The analysis consists of three phases.
In the first phase, you’ll create a layer of the areas the plant
should be outside of and another layer of the areas the plant
should be within.
In phase two, you’ll use these layers to select a subset of
parcels that are in a suitable location. You’ll then select the
subset of these that are vacant to create a layer of suitable
parcels.
In the third phase, you’ll consider the city’s additional
criteria that define the highly suitable parcels. You’ll find
the suitable parcels within 50 meters of a road and those
within 500 and 1,000 meters of the wastewater junction,
then tag them with the appropriate codes so they can be
identified on the map. You’ll also check to see which
parcels are large enough for the construction of the plant.
While the schematic shows the major steps in the process,
there are a number of interim steps you’ll complete in each
phase. You’ll develop the detailed methodology and
perform the analysis in Chapter 7, ‘Performing the
analysis’.
Step 4: Present the results
During project planning you should consider the purpose
and audience for your final products. For this project,
you’ll present the results of the analysis on a presentationquality
map that shows the parcels that are suitable and
highly suitable sites. The map will be presented to a general
audience at a public meeting.
While you don’t need to design the map layout at this point,
you’ll want to consider the layers that will be shown on the
map. In addition to the analysis layers, you may want to
include other layers that will provide context for the analysis
results and make the map easier to read and understand.
For this project, in addition to the layers you’ll use and
create during the analysis, you’ll want to show the
elevation grid as a backdrop so map readers can see the
areas of lower and higher elevation in the city, as elevation
has a major impact on the location of the wastewater
treatment plant.
You’ll design and create the presentation map in Chapter 8,
‘Presenting the results’.
What’s next?
Now that you’ve reviewed the steps involved in a GIS
project, identified the project objectives, and engaged in
some project planning, it’s time to get started.
You’ll assemble the data for the project and review the data
in the next chapter.
Ch04.pmd 2/16/2005, 1:17 PM76
IN THIS CHAPTER
77
Assembling the database
5
• Organizing the project database
• Adding data to the project folder
• Previewing the data in ArcCatalog
• Examining the data in ArcMap
• Cleaning up the Catalog tree
The data you will need for the project exists in several places and in
different formats. In order to conduct your analysis, you must find the data,
get information about it, and copy it into the appropriate workspace.
ArcCatalog lets you explore and organize your data efficiently.
In this chapter, you will organize your project database to hold the data that
you will obtain or create. You will use ArcCatalog to preview data and copy
it, create folders to hold data, and create layers to represent remote data.
Organizing your project database in a single branch of the Catalog tree
makes it easier to find the data you need, so you’ll create a connection to
the project folder.
You’ll also use ArcMap to display the datasets in your project database so
you can see the geographic relationships between the various datasets
you’ll be working with during the analysis.
By previewing the data in ArcCatalog and ArcMap, you’ll be able to see
which layers will need additional processing to be usable for the analysis.
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78 GETTING STARTED WITH ARCGIS
Organizing the project database
There are many ways to organize a project database.
One good strategy is to create a single project folder, then
subfolders to hold the input datasets, and another subfolder
to hold the datasets you create during the analysis.
As with many GIS projects, the data for your project comes
from several different sources. Some of it is in different
data formats or in different coordinate systems. Most of the
data has already been collected for you. Here is where the
data currently resides:
You’ll copy the data—to maintain the original as a
backup—and organize it in a single project folder to make it
more accessible. You’ll also create a new folder to store the
data you’ll create during the analysis.
There is no single way to structure a project database; it
partly depends on personal preference. The goal is to
minimize duplication of datasets and to have the data well
organized and easily accessible. This will help avoid
confusion during the project as well as if you need to
revisit the project in the future. Before you start to create
the folders on disk and move the datasets around, it’s a
good idea to sketch out the organization of the project
folders.
The City_share, County_share, and State_share folders are
stored locally on your computer, but they could represent
shared folders accessed over a network. You can use
ArcGIS to manage and display GIS data on any shared
drive on your network.
You’ll also want to think about how to name the new
datasets you’ll create and to also create naming
conventions. Using meaningful names can help you see at a
glance what each dataset is. For example, if you merge two
parcel datasets, you might name the output parcel01mrg to
indicate that it was the first parcel dataset created and the
LAYER NAME FORMAT CURRENT LOCATION
ELEVATION ELEVATION GRID STATE_SHARE FOLDER
ELEVATION < 563 M LOWLAND SHAPEFILE STATE_SHARE FOLDER
FLOODPLAIN FLOOD_POLYGON GEODATABASE
GREENVALLEY BD
GEODATABASE
RIVER RIVER SHAPEFILE COUNTY_SHARE FOLDER
PARCELS
PARCEL ,1_
PARCEL 2_
SHAPEFILES (TILED) CITY_SHARE\LAND FOLDER
PARKS PARKS_POLYGON GEODATABASE
GREENVALLEY BD
GEODATABASE
HISTORIC PARK HISTORIC.TIF SCANNED IMAGE CITY_SHARE\IMAGE FOLDER
WASTEWATER JUNCTION JUNCTION COVERAGE CITY_SHARE\UTILITY FOLDER
STREETS STREET_ARC GEODATABASE
GREENVALLEY BD
GEODATABASE
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ASSEMBLING THE DATABASE 79
operation was a merge. If you then edit the dataset, you
might name the edited version parcel02edt, and so on.
You’ll useArcCatalog to copy the folder containing the
shared data to a new location so you can work with it while
maintaining the original data. You’ll then create the new
personal geodatabase to hold several of the new datasets
you’ll create. You’ll also create the two new folders: one to
contain the layers from the city’s GreenvalleyDB
geodatabase and another to contain the layers you create
during the analysis. Here are the steps:
• Copy the project folder.
• Create a connection to the project folder.
• Create the WaterProject personal geodatabase in the
project folder.
• Create the City_layers folder in the project folder.
• Create the Analysis folder in the project folder.
If you have not already done the tutorial in Chapter 2,
‘Exploring ArcCatalog and ArcMap’, you will need to
check with your system administrator to learn where the
tutorial data is installed. Before you start the project you
will also need to make a folder connection in ArcCatalog to
the Greenvalley folder (use the instructions in Chapter 2).
Copying the project folder
The project folder contains data that other organizations are
sharing with you. You’ll copy the whole folder to your own
drive.
1. Click Start, point to Programs, point toArcGIS, and click
ArcCatalog.
2. Navigate to the ArcGIS\ArcTutor\Getting_Started folder.
Double-click the Getting_Started folder to show its
contents.
3. Click the project folder, hold the Ctrl key, drag the folder
from its current location, and drop it onto your C:\ drive
or any other local drive or folder.
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80 GETTING STARTED WITH ARCGIS
Substitute your local drive or folder for C:\ for the rest of
this chapter.
Dragging a folder to another drive—for example, from the
C:\ drive to the D:\drive—copies the folder and its contents
to the new location. Dragging to another location on the
same drive moves the folder. To copy a folder to another
location on the same drive, hold the Ctrl key while you
drag.
4. When ArcGIS is finished copying the data, click C:\ in
the Catalog tree to view the contents of the C:\ drive on
the right side of the Catalog window.
You can see that the project folder is listed.
Now that you’ve copied the project folder, you can work on
your copy of the data without modifying the original data.
Connecting to the project folder
If you have many folders on a drive, it can become tedious
to scroll to one you use frequently. Making a connection
puts that folder at your fingertips. You’ll create a
connection for the project folder.
In the tutorial, you made a folder connection by clicking
Connect to Folder and browsing. Here is a quicker way:
1. Click the List button . Navigate to the project folder
in the right side of the Catalog window (the Contents tab
should be selected).
2. Click the project folder and drag and drop it onto Catalog
at the top of the Catalog tree.
The new folder connection—C:\project—is now listed in
the Catalog tree.
The connection is a shortcut to the project folder. For the
rest of the project, you’ll access the data in the project
folder using this connection.
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ASSEMBLING THE DATABASE 81
Creating a personal geodatabase
Next, you’ll create a personal geodatabase within the
project folder to store several of the updated and new
datasets you’ll create during the project. Using a
geodatabase is an efficient way of storing, accessing, and
managing data.
1. Click the project folder connection you just created to
see its contents in the right side of the Catalog window.
2. Right-click the project folder connection, point to New,
and click Personal Geodatabase.
You will see additional options if you are usingArcInfo.
The new geodatabase is listed in the right side of the
Catalog window with its name highlighted (New
Personal Geodatabase).
3. Rename the geodatabase by typing “WaterProject” over
the highlighted text. Press Enter.
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82 GETTING STARTED WITH ARCGIS
Creating the City_layers and Analysis folders
Now you’ll create two new folders under the project folder
to hold the layers from the city’s GreenvalleyDB
geodatabase and the new layers you’ll create later during
the analysis.
1. Right-click the project folder, point to New, and click
Folder.
The new folder is listed on the right side of the Catalog
window with its name highlighted—New Folder.
2. Rename the folder by typing “City_layers” over the
highlighted text. Press Enter.
Create the Analysis folder the same way.
3. Right-click the project folder, point to New, and click
Folder. Rename the folder “Analysis”.
If you make a mistake and create the folder in the wrong
location or misspell the name, simply right-click the folder,
click Delete or Rename, and start over.
Ch05.pmd 2/16/2005, 1:18 PM82
ASSEMBLING THE DATABASE 83
Adding data to the project folder
Three of the data sources you need—parks, streets, and the
flood zone—are in the city’s GreenvalleyDB database,
which is already on your local drive. Since you’ll be
modifying the parks feature class by adding the new
historic park, you’ll copy it to the WaterProject
geodatabase you just created. That way, you maintain the
original data as a backup. You won’t be modifying the
other two feature classes—only using them for display and
analysis. Rather than copying them, you’ll create layers in
the project folder that point to the original data in the
GreenvalleyDB geodatabase. This will let you access the
data from within the project folder without creating
duplicate datasets. This is especially useful when accessing
data over a network. Here are the steps:
• Copy the parks feature class from the GreenvalleyDB
geodatabase to the WaterProject geodatabase.
• Create the streets layer in the City_layers folder.
• Create the flood_zone layer in the City_layers folder.
Copying the parks feature class to the
WaterProject geodatabase
1. Click the plus sign next to the project folder in the
Catalog tree to expand the contents.
2. Double-click the Greenvalley folder connection in the
Catalog tree.
The contents appear in the right side of the Catalog
window.
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84 GETTING STARTED WITH ARCGIS
In the tutorial in Chapter 2, you created a connection to the
Greenvalley folder. If the connection is no longer active,
navigate to the Getting_Started folder, expand its branches,
and click the Greenvalley folder.
3. In the Catalog tree, double-click Data, double-click
GreenvalleyDB, and double-click the Parks feature
dataset.
The GreenvalleyDB geodatabase is organized using feature
datasets such as hydrology and transportation. Feature
datasets are useful for grouping related feature classes
within a geodatabase. For example, you might include
feature classes, such as water mains, laterals, junctions, and
pumps, within a feature dataset named WaterSystem. All
the feature classes within a feature dataset have the same
geographic extent. In addition, the feature classes maintain
some common topological relationships. So, for example, if
you edited the junction feature class and moved the location
of a water junction, the attached lines in the mains and
lateral feature classes would move accordingly.
Since the WaterProject geodatabase you created will
contain only a few feature classes, it’s not necessary to use
feature datasets.
4. Click and drag the parks_polygon feature class to the
WaterProject geodatabase in the Catalog tree. Scroll
down if the WaterProject geodatabase isn’t visible.
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ASSEMBLING THE DATABASE 85
5. Click OK on the Data Transfer dialog box that appears.
6. When the transfer is complete, click the plus sign next to
the WaterProject geodatabase in the Catalog tree.
The parks_polygon feature class is listed.
Creating the streets and flood zone layers
Unlike the parks feature class, you won’t be modifying the
streets and flood zone data—you’ll simply be using the data
in the analysis process. So, rather than copying the data into
the project folder, you’ll create layers to serve as shortcuts
to the data. That way, you maintain a single copy of the
data in the GreenvalleyDB but will be able to access the
data from within the project folder.
The contents of the GreenvalleyDB geodatabase should still
be visible in the Catalog tree. If not, double-click the
Greenvalley folder to show its contents, then double-click
Data, and double-click GreenvalleyDB.
1. Double-click Transportation.
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86 GETTING STARTED WITH ARCGIS
2. Right-click street_arc and click Create Layer.
3. In the Save Layer As dialog box, navigate to the
City_layers folder in your project folder and type
“streets” to name the layer. Click Save.
The streets layer is created in the City_layers folder.
Use the same procedure to create a layer for the flood zone
data.
1. Double-click the Hydrology feature dataset in the
Catalog tree, right-click the flood_polygon feature class,
and click Create Layer.
2. Navigate to the City_layers folder in your project folder
and type “flood_zone” to name the layer. Click Save.
3. Click the project folder in the Catalog tree and doubleclick
the City_layers folder.
The two layers are listed; you may need to click Refresh
on the View menu to see them.
The streets and flood_zone layers are now stored with your
project data. The actual data for each layer is stored in the
GreenvalleyDB database. This database is on your local
drive in this case, but it could just as easily be a remote
database accessed over a network.
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ASSEMBLING THE DATABASE 87
At this point, you’ve organized all the existing project data.
Now you can access all the data from within the project
folder. Your project folder should look like this:
You may need to open each folder and the geodatabase to
see all the layers.
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88 GETTING STARTED WITH ARCGIS
Previewing the data in ArcCatalog
So far you’ve organized the project data by copying data
folders and files. It’s a good a idea to review each dataset
to see what the spatial data looks like and what attributes it
has. Doing so will help you make sure you’ve assembled
the datasets you need. You will also be able to determine if
any of the data needs additional processing to be usable for
the analysis.
You have several options for examining the data.
ArcCatalog lets you quickly preview the features and
attributes in each individual dataset. ArcMap lets you
display the datasets together, change how they’re displayed,
and zoom in on them to take a closer look. You’ll use both
ArcCatalog and ArcMap to review your data.
Previewing the streets and flood_zone layers
1. Navigate to and click the flood_zone layer in the Catalog
tree.
The right side of the Catalog window displays the name
of the layer, along with its type and a gray square
containing an icon representing the flood_zone polygons.
2. Click the Preview tab.
The flood_zone polygons are displayed.
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ASSEMBLING THE DATABASE 89
While you’re here, you can create a thumbnail view of the
flood_zone layer. This will let you quickly see what the
layer looks like as you navigate through the Catalog tree.
Since you just created the layers, the thumbnails don’t exist
yet.
3. Click the Create Thumbnail button on the toolbar.
Nothing happens on the screen, but the thumbnail is
created and stored with the flood_zone layer.
4. Click the Contents tab.
Rather than the gray square you saw previously, you see
the thumbnail showing the actual flood_zone polygons.
Now preview and create a thumbnail for the streets layer.
5. Click the streets layer in the Catalog tree and click the
Preview tab.
The streets are displayed.
6. Click the Create Thumbnail button on the toolbar.
7. Click the Contents tab to see the thumbnail.
Create Thumbnail
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90 GETTING STARTED WITH ARCGIS
8. Click the City_layers folder in the Catalog tree, then
click the Thumbnails button on the toolbar.
The thumbnails you just created for these layers are
displayed.
Thumbnails are useful for quickly previewing all the spatial
data in a particular folder or geodatabase.
Exploring the other data folders
You can preview the other datasets by looking at the
contents of the other folders in the project database. The
thumbnails for these datasets already exist.
1. Click the plus sign next to the City_share folder in the
Catalog tree to list its contents.
2. Click the image folder.
Since the Contents tab is selected and the Thumbnail
button on the toolbar is also selected, the thumbnail for
the historic park TIFF file displays.
3. Click the land folder to see the two parcel shapefiles
you’ll be working with, then click the utility folder to see
the water junction coverage.
4. Click the State_share folder to display the thumbnails for
the elevation grid and lowland shapefile.
The State_share folder also contains a file named
state_dot.prj that contains the coordinate system definition
for Department of Transportation data. Your colleague at
the state DOT wisely included it in case there was a
question about the coordinate system of the elevation
datasets. Since it’s not a geographic dataset, there is no
thumbnail.
Previewing the river shapefile
The County_share folder contains the river shapefile
created by the County Water Resources Department.
1. Double-click County_share to show the folder’s
contents, if necessary.
Thumbnails
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ASSEMBLING THE DATABASE 91
The river thumbnail appears. The shapefile contains a
single river. You can take a closer look to make sure you
have the right shapefile.
2. Click the Preview tab.
You get a message saying “The selection cannot be
previewed.” That’s because the County_share folder is still
selected.
The Preview tab previews a single dataset only. In contrast,
the Contents tab displays all the datasets in a folder or
geodatabase as thumbnails, a list, or icons representing the
datasets. The Contents tab will also show you the contents
of a single dataset. For shapefiles, feature classes, or image
files, it displays the name and type of the dataset, along with
the thumbnail. For coverages, the Contents tab lists the files
comprising the coverage.
3. Click the river shapefile in the Catalog tree.
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92 GETTING STARTED WITH ARCGIS
Now the river is displayed. You can check its attributes
to be sure this is the right river.
4. Click the Preview dropdown arrow and click Table.
Now you can see the feature attribute table for the river
shapefile. Your project area is along the Green River.
This is the right shapefile.
You’re finished previewing the data in ArcCatalog for now.
5. Click the Contents tab.
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ASSEMBLING THE DATABASE 93
Examining the data in ArcMap
The Contents and Preview tabs in ArcCatalog give you a
quick overview of what your data looks like. However, the
thumbnail images aren’t drawn to scale or in the correct
geographic space. Plus, each dataset is displayed
separately. To see how the datasets relate to each other
geographically, you need to display them in ArcMap. This
will let you confirm that the datasets all overlap with your
study area.
Opening a new map
1. Click the Launch ArcMap button in ArcCatalog to start
ArcMap.
2. If the startup dialog box appears, click the option to use
A new empty map and click OK.
If the startup dialog box doesn’t appear, ArcMap
automatically opens a new map.
You can think of ArcMap as providing two functions: (1) a
workbench, or desktop, where you view, query, edit, and
combine geographic data and (2) a canvas, or page, where
you compose (layout) maps for display. You usually work in
Data view for the former and Layout view for the latter,
although you can also work with the data in Layout view.
Data view is the default when you start a new map. You’ll
do most of the work for your project in Data view. You’ll
work with Layout view in Chapter 8, ‘Presenting the
results’.
Launch ArcMap
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94 GETTING STARTED WITH ARCGIS
Adding the parcel layers to the map
The two parcel layers you’ve obtained from the city
assessor’s office constitute the area in which you’ll focus
your search for a wastewater treatment plant site. You’ll
combine the two layers in the next chapter, but for now you
can display them together to get a better sense of the area
you’ll be working in.
There are two ways to add data to a map. You can use the
Add Data button on the ArcMap toolbar and navigate to the
location of the dataset, or you can drag datasets from
ArcCatalog and drop them on the map. The end result is the
same, so which you use is a matter of preference. You’ll get
a chance to use both in this section.
1. Click the Add Data button on the ArcMap toolbar.
2. Navigate to the City_share folder under the project
folder.
3. Double-click the land folder.
4. Click the parcel_1 shapefile, then press the Shift key and
click the parcel_2 shapefile so both are selected.
5. ClickAdd.
The parcels are listed in the table of contents and
displayed on the map. You can see that they’re adjacent.
When you add a dataset to a map, ArcMap uses a color
that it selects. The colors on your map may not match the
ones shown here. You can change the colors and symbols
for the layers on your map, as you’ll see later in this
chapter.
Add Data
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ASSEMBLING THE DATABASE 95
Adding the rest of the city data to the map
Now you’ll add to the map the streets and flood_zone
layers from the City_layers folder, the parks feature class
from the WaterProject geodatabase, and the wastewater
junction coverage from the City_share folder. As an
alternative to adding data to a map using the Add Data
button, you can add data simply by dragging the datasets
from ArcCatalog.
1. Make sure both the ArcCatalog and ArcMap windows
are visible.
2. In the Catalog tree, navigate to the project folder.
3. Double-click City_layers, if necessary, to display its
contents.
4. Click flood_zone and drag it onto the map.
The flood_zone feature class is drawn on the map.
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96 GETTING STARTED WITH ARCGIS
5. Click the streets layer and drag it onto the map.
6. In the Catalog tree, open the utility folder under the
City_share folder. Click and drag the junction coverage
onto the map.
7. Finally, open the WaterProject geodatabase, if
necessary, and click and drag the parks_polygon feature
class onto the map.
Now you’ve displayed most of the project datasets,
stored in various folders and in different formats, all on
the same map.
By default, ArcMap draws point features, such as the
junction, on top of line features, such as the streets. It
draws polygon features under the others. Within each type,
the drawing order depends on the order the data was added
to the map, with the most recent addition on top. You can
rearrange the drawing order by clicking and dragging
layers up or down in the table of contents. You can also
choose your own colors and symbols for the layers.
Since the flood_zone layer is drawn on top of the parcels, it
partially obscures them. You’ll display the parcel outlines
on top of the flood_zone so you can see the flood_zone
beneath.
8. In the ArcMap table of contents, click the flood_zone
layer and drag it to the bottom.
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ASSEMBLING THE DATABASE 97
9. Right-click the legend symbol under parcel_1.
10. Click No Color at the top of the color palette.
Do the same for parcel_2.
11. Right-click the legend symbol under parcel_2 and click
No Color on the color palette.
The parcel outlines are displayed, and you can see the
flood zone area underneath.
You’re still zoomed in to the study area delineated by the
parcel shapefiles. To get the big picture, zoom to the full
extent of the datasets.
12. Click the Full Extent button on the Tools toolbar.
Full Extent
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98 GETTING STARTED WITH ARCGIS
Now the map extent includes the additional datasets
you’ve added to the map. You can see where the parcels
you’re focusing on are in relation to the rest of the city.
Adding the river shapefile to the map
Next you’ll add the river shapefile, from the County Water
Resources Department, to the map.
1. Click the Add Data button on the ArcMap standard
toolbar.
2. Navigate to the County_share folder under the project
folder.
3. Click river.shp and clickAdd.
ArcMap displays a message that the river shapefile has
a geographic coordinate system that differs from other
data in the map. All the datasets you’ve added up to this
point are from the city, and all use the same geographic
coordinate system (Transverse Mercator). Apparently,
the river shapefile uses a different coordinate system
than the city data.
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ASSEMBLING THE DATABASE 99
Every dataset uses a geographic coordinate system to link
the coordinates stored in the GIS to actual locations on the
surface of the earth. The coordinate system allows the GIS
to determine where geographic features are located in
relation to each other. There are many different coordinate
systems used with geographic data. You can display the
coordinate system for a dataset in ArcCatalog. ArcToolbox
lets you define or change the coordinate system for a
dataset. You’ll get a chance to do this in the next chapter,
where you’ll also learn more about what a coordinate
system is.
When you create a new map in ArcMap, the coordinate
system used by the first dataset you add to the map, in this
case the parcel_1 shapefile, defines the coordinate system
for the entire map. If you add a dataset that doesn’t use that
same coordinate system, ArcMap will attempt to transform
it on the fly so it displays correctly with the other data.
4. Click OK to close the Warning message box.
ArcMap transforms the river to the same coordinate
system as the other datasets so it can be displayed.
You could just leave the shapefile in its original coordinate
system, but since it will eventually be added to the city’s
GreenvalleyDB geodatabase, you’ll want to put it in the
same coordinate system as the rest of the city’s data. You’ll
do that in the next chapter.
Adding the elevation data to the map
Next you’ll take a look at the elevation data from the state
Department of Transportation.
1. Click the Add Data button and navigate to the
State_share folder.
2. Click elevation and clickAdd.
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100 GETTING STARTED WITH ARCGIS
As with the river shapefile, ArcMap warns you that this
dataset has a coordinate system that differs from other
data on the map. Apparently the elevation data is also in
a coordinate system different from that used by the city
for its data.
3. Click OK to close the Warning message box. ArcMap
adds the elevation grid to the map.
Since the grid is raster data, which is displayed as a
continuous layer, it is added to the bottom of the table of
contents and is drawn beneath the other layers. You can see
that the grid doesn’t underlie the entire city but does
coincide with your study area.
Now add the lowland shapefile to the map.
4. Click theAdd Data button and click lowland.shp, then
clickAdd.
ArcMap warns you that the layer is missing spatial
reference information and can’t be projected.
ArcMap can only transform data on the fly if the data is in
latitude–longitude, which ArcMap can recognize, or if the
coordinate system for the data has been previously defined,
as it was for the elevation grid.
Apparently, the coordinate system was not defined for the
lowland shapefile when it was created from the elevation
grid. Presumably, it is in the same coordinate system as the
elevation grid, but ArcMap doesn’t know that at this point.
5. Click OK to close the Warning box.
ArcMap adds the data. You’ll notice that while lowland
appears in the table of contents, it doesn’t appear on the
map (it should appear on top of the layers that are listed
below it in the table of contents). That’s because it’s in
another—unknown at this point—coordinate system, so
it can’t be displayed correctly with the other data.
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ASSEMBLING THE DATABASE 101
6. Click the Full Extent tool.
There is a tiny dot at the bottom of the screen (that’s the
lowland shapefile) and a slightly larger dot at the top of
the screen—that’s the rest of the data. ArcMap adjusts
the extent to the full range of coordinate values in both
coordinate systems and draws all the layers within that
extent.
7. Right-click lowland in the table of contents and click
Zoom To Layer.
Full Extent
Lowland layer
All other layers
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102 GETTING STARTED WITH ARCGIS
Now you can see the lowland shapefile but not the rest
of the data. You’ll define the coordinate system for
lowland in the next chapter so you can display and
overlay it with the other data.
8. Click the Go Back to Previous Extent tool, then click it
again.
The other datasets should now be displayed.
Creating a layer from the elevation grid
By default, the elevation grid is displayed using a grayscale.
You’ll be displaying the elevation grid on the final map later
in the project, so while you’re here, you’ll create a new
layer with the symbology you want to use.
1. Right-click elevation in the table of contents and click
Properties.
Go Back to
Previous
Extent
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ASSEMBLING THE DATABASE 103
The Properties dialog box appears.
2. Click the Symbology tab.
3. Click the Color Ramp dropdown arrow, scroll down to
the color ramp appropriate for representing elevation
(from orange through yellow and green to blue), and
click it.
The default for this ramp is orange for low values and blue
for high. You want to reverse the color ramp for the
elevation grid.
4. Check the Invert check box.
5. Click the Display tab and type “50” in the Transparent
text box.
This will make the colors less intense, so it will be easier
to see the other layers displayed on top of the grid.
3
4
5
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104 GETTING STARTED WITH ARCGIS
6. Click OK. The grid is displayed using the color ramp and
transparency settings you specified.
So far, the display settings for the elevation grid are valid
only for the current map. To make sure the grid is displayed
this way when you create your final map, you’ll save it as a
layer file.
7. Right-click elevation and click SaveAs Layer File.
The Save Layer dialog box appears.
8. Navigate to the City_layers folder, name the layer
“elevation_grid”, and click Save.
Now when you want to display the elevation grid again, you
can just add the elevation_grid layer to the map and it will
be drawn using the display settings you specified.
Layers store a shortcut to a data source and, optionally,
information about how the data should be displayed on the
map. Any time you add a dataset to a map in ArcMap, you
create a layer since the map stores the data source and the
symbology associated with it. When you save the map, the
layer information is also saved.
As you’ve seen, you can also create layers as separate
files. These layer files can be used to store symbology and
other information, so the data is displayed the same way
each time it is added to a map (as you just did with the
elevation grid layer). They can also be used to access a
data source without having to navigate to the actual location
of the data (as you did earlier with the streets and
flood_zone layers).
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ASSEMBLING THE DATABASE 105
Saving your map
The map you’ve been using to assemble your project
database is a working map. You’ll be displaying and using
some of these same layers in the next chapter. Save the
map now so you can use it in the next chapter and won’t
need to add the layers again.
1. Click File and click Save.
2. Navigate to the project folder.
3. Type “wastewater data” in the File name text box.
4. Click Save.
The map is saved as a map file. Notice that the name of
the map now appears in the title bar.
You’re done using ArcMap for the time being, so go ahead
and close it.
5. Click File and click Exit, or simply click the Close button
(X) in the upper-right corner of the ArcMap window.
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106 GETTING STARTED WITH ARCGIS
Cleaning up the Catalog tree
At this point, you’ve made folder connections, created and
copied folders, and created layers to organize your project
database. The Catalog tree in ArcCatalog is beginning to
appear cluttered. Before you begin working with the data in
the next chapter, clean up the Catalog tree. This will make
it easier to find the data you need later.
The connection to the tutorial folder you created in
Chapter 2 is unnecessary now that you have copied the
project folder and the files supplied by the city, county, and
state. Deleting this connection will make more room in the
tree.
1. Right-click theArcGIS\ArcTutor\Getting_Started\
Greenvalley folder connection and click Disconnect
Folder.
The folder connection is removed from the Catalog tree.
Now the Catalog shows only the data that you need for the
project. You may need to click View and click Refresh or
close and reopen ArcCatalog to see the elevation_grid layer
and the wastewater data map you created since you last
used ArcCatalog.
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ASSEMBLING THE DATABASE 107
In this chapter, you assembled the available data into an
organized project database and reviewed the data. Some of
the data will need additional processing before you can use
it in the analysis. The two adjacent parcel tiles will need to
be merged into one layer. You’ll also need to transform the
river shapefile into the same coordinate system as the rest
of the city’s data since it will become part of the city’s
permanent database. Since the elevation data will only be
used for this project, you don’t need to transform the data,
but you do need to define the coordinate system for the
lowland shapefile. Finally, you’ll recall from the project
planning in Chapter 4, ‘Planning a GIS project’, that you’ll
need to update the parks layer to include the new historic
park. Here’s a list of the layers you’ll be working with, their
new locations in the project folder, and the processing
required for each.
You’ll undertake the data preparation tasks in the next
chapter. If you’re continuing on, keep ArcCatalog open.
NAME FORMAT LOCATION PROCESSING
ELEVATION GRID STATE_SHARE FOLDER NONE
LOWLAND SHAPEFILE STATE_SHARE FOLDER DEFINE COORDINATE SYSTEM
FLOOD_ZONE LAYER FILE (FROM GEODATABASE) CITY_LAYERS FOLDER NONE
RIVER SHAPEFILE COUNTY_SHARE FOLDER
DEFINE COORDINATE SYSTEM; PROJECT TO CITY'S
COORDINATE SYSTEM; EXPORT TO GEODATABASE
PARCEL ,1_
PARCEL 2_
SHAPEFILES (TILED) CITY_SHARE\LAND FOLDER MERGE TILES INTO GEODATABASE FEATURE CLASS
PARKS_POLYGON GEODATABASE WATERPROJECT GEODATABASE UPDATE WITH NEW HISTORIC PARK
HISTORIC.TIF SCANNED IMAGE CITY_SHARE\IMAGE FOLDER DIGITIZE INTO PARKS FEATURE CLASS
JUNCTION COVERAGE CITY_SHARE\UTILITY FOLDER NONE
STREETS LAYER FILE (FROM GEODATABASE) CITY_LAYERS FOLDER NONE
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Ch05.pmd 2/16/2005, 1:18 PM108
IN THIS CHAPTER
109
Preparing data for analysis
6
• Data preparation tasks
• What are coordinate systems?
• Defining the coordinate system for
the elevation data
• Preparing your scripting
environment
• Projecting the river shapefile
• Exporting the river shapefile to the
geodatabase
• Digitizing the historic park
• Merging the parcel layers
Now that you have collected and organized the available data, you’ll need to
prepare the data for analysis. Some of your data is usable as is, but some
needs additional processing. Making data usable for analysis can encompass
a variety of tasks.
Unless GIS data is in the same coordinate system, it will not display or
overlay correctly. ArcMap is able to match the coordinate systems of
two different data sources, so you can display them together, as long as the
coordinate systems are defined for both. However, if the data will become
part of a permanent GIS database, you’ll want to make sure it is in the same
coordinate system and same data format as the rest of the database.
You may need to update or modify existing features based on more recent
information. This can include modifying or adding spatial features or
changing or adding values in a dataset’s attribute table.
Features are sometimes stored as sets of adjacent tiles, such as map sheets
in a series. For analysis, it’s often easier to join adjacent datasets into a
single set of features so you can work with all the features at once.
You may also need to obtain new data for your project based on the
requirements of the analysis. In some cases you may be able to get data in a
usable format from another organization locally or on the Internet—either
for free or by buying it from a commercial source. In other cases, you’ll
need to create the data by digitizing or scanning from a paper map or
converting the data from a table or list, such as a list of customer addresses.
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110 GETTING STARTED WITH ARCGIS
For this project, you’ll need to perform several tasks to
prepare your data for analysis. You’ll be working with data
from various sources and in various formats: shapefiles,
geodatabase feature classes, coverages, and rasters.
ArcGIS lets you display and combine data in these formats
without converting it.You’ll define the coordinate system
for the lowland shapefile so it can be displayed and
combined with the other data. Then you’ll project the river
shapefile to the same coordinate system as the city’s
existing data and export it to the WaterProject geodatabase
so it’s ready to be placed into the city’s geodatabase. The
section ‘What are coordinate systems?’, later in this
chapter, provides a brief overview of coordinate systems
and map projections.
You’ll also update the parks feature class with the new
historic park so it, too, will be ready to be placed back into
the city’s geodatabase. Finally, you’ll merge the two parcel
layers that comprise your study area.
Here are the processing steps to prepare the data for
analysis:
• Define the coordinate system for the elevation data.
• Project the river shapefile to the city’s coordinate
system.
• Export the river shapefile to the WaterProject
geodatabase.
• Digitize the historic park into the parks feature class.
• Merge the parcel layers.
You’ll primarily be working with shapefiles since that’s how
most of the data came to you, but you’ll also be working
with data in the WaterProject personal geodatabase. A
personal geodatabase is useful for processing data on a
local computer that will become part of a large, multiuser
geodatabase.
Data preparation tasks
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PREPARING DATA FOR ANALYSIS 111
What are coordinate systems?
ArcGIS stores features using x,y coordinates. These
coordinates are linked to real-world locations by a
coordinate system. The coordinate system specifies a
datum and a map projection.
Datum
A datum is a mathematical representation of the shape of
the earth’s surface. A datum is defined by a spheroid, which
approximates the shape of the earth and the spheroid’s
position relative to the center of the earth. There are many
spheroids that represent the shape of the earth and many
more datums based on them.
A horizontal datum provides a frame of reference for
measuring locations on the surface of the earth. It defines
the origin and orientation of latitude and longitude lines.A
local datum aligns its spheroid to closely fit the earth’s
surface in a particular area; its origin point is located on the
surface of the earth. The coordinates of the origin point are
fixed, and all other points are calculated from this control
point. The coordinate system origin of a local datum is not
at the center of the earth. NAD27 and the European Datum
of 1950 are local datums.
In the last 15 years, satellite data has provided geodesists—
mathematicians concerned with the precise measurement of
the shape and size of the earth—with new measurements to
define the best earth-fitting ellipsoid, which relates
coordinates to the earth’s center of mass. Unlike a local
datum, an earth-centered, or geocentric, datum does not
have an initial point of origin. The earth’s center of mass is,
in a sense, the origin. The most recently developed and
widely used datum is the World Geodetic System of 1984
(WGS84). It serves as the framework for supporting
locational measurement worldwide. GPS measurements are
based on the WGS84 datum.
Earth-centered
datum coordinate
system
Local datum
coordinate
system
Local datum
Earth’s surface
Earth-centered datum (WGS84)
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112 GETTING STARTED WITH ARCGIS
Map projection
Map projections are systematic transformations of the
spheroidal shape of the earth so that the curved, threedimensional
shape of a geographic area on the earth can be
represented in two dimensions, as x,y coordinates.
Maps are flat, but the surfaces they represent are curved.
Transforming three-dimensional space onto a twodimensional
map is called projection. Projection formulas
are mathematical expressions that convert data from a
geographical location—latitude and longitude—on a sphere
or spheroid to a representative location on a flat surface.
Projection
Earth’s
surface
Map surface
This process inevitably distorts at least one of the following
properties: shape, area, distance, or direction. For small
areas, such as a city or county, the distortion will probably
not be great enough to affect your map or measurements.
If you’re working at the national, continental, or global level,
you’ll want to choose a map projection that minimizes the
distortion based on the requirements of your specific
project.
For more information on coordinate systems, datums, and
map projections, see the books Understanding Map
Projections and Modeling Our World: The ESRI Guide
to Geodatabase Design.
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PREPARING DATA FOR ANALYSIS 113
Defining the coordinate system for the elevation data
The elevation grid and lowland file are in a different
coordinate system from the rest of the data. That’s not a
problem as long as the coordinate system is defined for
those datasets. Without this information, however, ArcMap
can’t do a geographic transformation, and the data can’t be
displayed or overlaid with the other project data. While the
coordinate system for the elevation grid is defined, when
the lowland shapefile was created from the grid, the
coordinate system information was not included. You need
to define the coordinate system for the shapefile.
If you closed ArcCatalog at the end of Chapter 5,
‘Assembling the database’, you’ll need to reopen it now.
Checking the coordinate system information
Before defining the coordinate system for the lowland
shapefile, you’ll check the coordinate system definitions for
the city data and for the elevation grid. You’ll do this by
examining the metadata for the datasets.
1. In ArcCatalog, navigate to the WaterProject
geodatabase under the project folder in the Catalog tree.
2. Open the database to list its contents, then click the
parks_polygon feature class.
This feature class, which you copied from the city’s
GreenvalleyDB, is in the same coordinate system as the
rest of the city’s data.
3. Click the Metadata tab.
4. Click the Stylesheet dropdown arrow and click FGDC
ESRI.
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114 GETTING STARTED WITH ARCGIS
5. Click the Spatial tab in the metadata panel.
You can see that the coordinate system for the
parks_polygon feature class uses a Transverse_Mercator
projection.
Metadata contains information about each dataset. Some of
the information is assigned and maintained automatically by
ArcGIS; other information you add interactively. Metadata
is invaluable when sharing datasets and for documenting
GIS projects.
In this project you’ll use metadata to get information you
need for several of the steps. Metadata lets you store a
great deal of information about a dataset: source,
processing status, data quality, attribute values, and much
more. For several of the datasets, we’ve provided some of
the key information you’ll need for the project.
In an actual GIS project you’d also use metadata to keep
track of modifications you make to existing datasets and to
document new datasets you create during the project.
Adding or updating the metadata for a dataset takes a little
extra time, but it pays off if you need to reuse the dataset in
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PREPARING DATA FOR ANALYSIS 115
the future, share it with another department or organization,
or reconstruct your processing steps.
Now check the coordinate system for the elevation grid.
6. Navigate to the State_share folder in the Catalog tree,
open it, and click elevation.
7. Click the Spatial tab. When you select a new dataset,
ArcCatalog defaults the metadata display to the
Description tab.
You can see that the elevation grid is in a coordinate system
that uses a Lambert_Azimuthal_Equal_Area projection.
Finally, check the coordinate system information for the
lowland shapefile.
8. In the State_share folder, click lowland.
9. Click the Spatial tab.
The metadata lists the bounding coordinates for the
shapefile but doesn’t list the coordinate system since it is
unknown.
When you previewed the data in Chapter 5, ‘Assembling
the database’, ArcMap was able to transform the elevation
grid on the fly and display it with the other project data
since the coordinate system was defined and stored with
the grid. Because the coordinate system for the lowland
shapefile is unknown, ArcMap was unable to transform it.
Defining the coordinate system for the lowland
shapefile
Presumably, the coordinate system for the lowland shapefile
is the same as for the elevation grid since the shapefile was
originally created from that grid. But you don’t know for
sure. Thoughtfully, the analyst at the Department of
Transportation who sent you the data also included a spatial
reference file that defines the coordinate system the
department uses for all its data. You’ll use the file
state_dot.prj to define the coordinate system for the
shapefile withinArcCatalog.
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116 GETTING STARTED WITH ARCGIS
1. Right-click lowland in the Catalog tree and click
Properties.
The Shapefile Properties dialog box appears.
2. Click the Fields tab.
The fields in the shapefile’s attribute table are listed. The
Shape field contains the coordinate information for the
shapefile.
3. In the Field Name list, click the row containing Shape.
The properties for the Shape field are displayed below in
the Field Properties list. You can see that the Spatial
Reference property is listed as Unknown.
4. Click the button with the ellipses (…) to the right of
Spatial Reference.
The Spatial Reference Properties dialog box appears.
3
4
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PREPARING DATA FOR ANALYSIS 117
You’ll be defining the coordinate system by selecting a
predefined coordinate system, specifically the one contained
in the state_dot.prj file that accompanied the elevation and
lowland data.
5. Click Select.
5
6. Navigate to the State_share folder under the project
folder connection, click state_dot.prj, and clickAdd.
The name of the coordinate system appears in the
Spatial Reference Properties dialog box, and the details
are listed. You can see that they’re the same as for the
elevation grid.
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118 GETTING STARTED WITH ARCGIS
7. Click OK to close the Spatial Reference Properties
dialog box.
The name of the coordinate system now appears in the
Field Properties list.
8. Click OK to close the Shapefile Properties dialog box.
You can verify the new coordinate system in the
metadata.
9. Click View and click Refresh, then click the Spatial tab.
You can see that the coordinate system for the lowland
shapefile is now defined.
With the coordinate system defined, the lowland shapefile
should now display correctly with the other project data and
can be used in overlay operations during the analysis. You
can check this in ArcMap.
10. Click the Launch ArcMap button on the toolbar.
Launch ArcMap
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PREPARING DATA FOR ANALYSIS 119
11. In the startup dialog box, click wastewater data.mxd and
click OK. If the startup dialog box doesn’t appear, click
File on the ArcMap toolbar and click wastewater
data.mxd.
The lowland layer now appears in the same geographic
space as the other project data.
Lowland shapefile
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120 GETTING STARTED WITH ARCGIS
12. Click lowland in the table of contents and drag it to the
bottom so it displays beneath the elevation grid.
You can see the layer under the elevation grid and see
that it does in fact encompass the lowest elevations in
the city.
13. Close ArcMap. You won’t be using this map again, so
click No when prompted to save changes to the map.
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PREPARING DATA FOR ANALYSIS 121
Preparing your scripting environment
Before you go any further, you need to make sure that you
have a scripting environment installed. The geoprocessing
tools in ArcGIS may be used in a number of scripting
environments, such as VBScript, JScript, and Python. In
this tutorial, you’ll be using Python, so you need to install it
on your system now if it is not already installed. (ArcGIS
automatically installs Python and PythonWin by default.)
1. Go to http://www.python.org and download the Python
Installer for the current Python version.
2. Run the installer package to install Python. This will
create a Python folder on your specified drive and
create a Python shortcut in the Programs menu.
3. To install PythonWin, go to http://starship.python.net/
crew/mhammond/win32/Downloads.html and download
the matching win32all version.
4. Run the win32all installer to install PythonWin. It will be
added to the Python folder on your specified drive.
Newer versions of Python can be installed, provided that
the appropriate version of the PythonWin application is also
installed. You can identify the appropriate version of the
PythonWin application to install based on your installed
version of Python at http://starship.python.net/crew/
mhammond/win32/Downloads.html.
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122 GETTING STARTED WITH ARCGIS
Projecting the river shapefile
The next task is to project the river shapefile into the same
coordinate system as the data in the city’s GreenvalleyDB
geodatabase. According to your colleague at the county
Water Resources Department, the river shapefile is in
geographic coordinates (latitude and longitude). The rest of
the data in the city’s database is in the Transverse Mercator
coordinate system, which is a projected coordinate system.
As long as a dataset is in geographic coordinates, ArcMap
can transform it on the fly to display and overlay it with the
other data (as you saw in the last chapter).
However, the river data will eventually be placed into the
city’s GreenvalleyDB database, so you’ll want to project it
into the same coordinate system as the rest of the city’s
data to be consistent.
Projecting the shapefile is a two-step process: first you’ll
define the coordinate system for the shapefile; then you’ll
define the output coordinate system and project the file.
You’ll do both of these tasks in ArcToolbox. ArcToolbox
contains a number of data management and conversion
tools and wizards.
Defining the coordinate system for the river
shapefile
1. In ArcCatalog, click the Show/Hide ArcToolbox button
on the toolbar.
The ArcToolbox window appears.
2. Double-click Data Management Tools in the ArcToolbox
tree; double-click Projections and Transformations, then
double-click the Define Projection tool. If you are using
ArcInfo you will see additional tools not shown here.
The Define Projection dialog box appears.
You defined the coordinate system for the lowland shapefile
using the Properties dialog box inArcCatalog. ArcToolbox
provides an alternate way of defining a coordinate system.
Show/Hide ArcToolbox
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PREPARING DATA FOR ANALYSIS 123
3. Click the Input Dataset or Feature Class browse button
and navigate to the County_share folder under the
project folder.
4. Click river.shp and clickAdd.
The shapefile is listed. The coordinate system is listed as
GCS_Assumed_Geographic_1. ArcGIS attempts to
determine the shapefile’s coordinate system based on the
dataset’s coordinate values. In this case, ArcGIS has
determined that the shapefile is in geographic coordinates—
latitude–longitude—however, you need to explicitly define
the geographic coordinate system before you can project
the data.
5. Click the button next to Coordinate System.
The Spatial Reference Properties dialog box appears.
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There are three ways of defining a coordinate system: using
a predefined coordinate system stored as a .prj file,
matching the coordinate system of an existing dataset by
specifying the name of the dataset, or interactively
specifying a projection and a datum and their associated
parameters. In this case, you’ll be specifying a predefined
coordinate system.
6. Click Select on the Spatial Reference Properties dialog
box.
The Browse for Coordinate System folder opens.
ArcGIS provides many predefined coordinate systems for
you to use, stored as .prj files. The files include all the
coordinate system parameters including the map projection
type and parameters, measurement units, and so on. You
can also define custom coordinate systems and save them
as .prj files—for example, the state_dot.prj file.
7. Double-click Geographic Coordinate Systems and
double-click NorthAmerica.
8. Click North American Datum 1983.prj and clickAdd.
The coordinate system information is displayed in the
Details window.
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9. Click OK to close the Spatial Reference Properties
dialog box.
10. Click OK.
11. Click Close to close the Define Projection dialog box.
The coordinate system of the river shapefile is now defined.
To verify this, in ArcCatalog navigate to the County_share
folder, click river, click the Metadata tab, and click the
Spatial tab. The coordinate system is now listed as
GCS_NorthAmerican_1983. You may need to close
ArcCatalog and restart it to see this.
Projecting the shapefile
When you define a coordinate system, you simply tell
ArcGIS what projection the dataset uses and what units the
coordinates are stored in. When you project a dataset, on
the other hand, ArcGIS actually creates a new dataset with
the coordinates transformed from the existing coordinate
units—in this case, decimal degrees—to a new coordinate
system—in this case, Transverse Mercator meters. You
specify the input dataset and the coordinate system to
project into, and ArcGIS creates the new dataset.
Because you have data that is already in the Transverse
Mercator coordinate system used by the city, you can
simply specify a dataset to match to. The Project tool will
get the coordinate system parameters from the existing
dataset and create a new river shapefile in that coordinate
system.
1. InArcToolbox, double-click Feature under Projections
and Transformations in the Data Management tools, then
double-click Project.
2. Click the Input Dataset or Feature Class browse button
and navigate to the County_share folder under the
project folder.
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3. Click river.shp and clickAdd.
You need to specify a name for the projected shapefile and
a location where it will be stored. You’ll put it in the
City_share folder since it will eventually become part of the
city’s database. You’ll name it river02prj since it will be the
second version of the river dataset and will have been
projected.
4. Click the Output Dataset or Feature Class browse button
and navigate to the project folder. Double-click
City_share, then type “river02prj” in the Name text box.
5. Click Save.
The City_share folder is listed as the location to store
the projected shapefile river02prj.
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6. Click the button next to Output Coordinate System.
The Spatial Reference Properties dialog box appears.
This is the same dialog box you used to define the
coordinate system for the lowland shapefile and the river
shapefile. In those cases you specified a spatial reference
(.prj) file. This time you’ll specify an existing dataset from
which to get the coordinate information. You know the
parks feature class is in the right coordinate system since
you copied it directly from the city’s existing geodatabase.
7. Click Import and navigate to the WaterProject
geodatabase under the project folder connection.
8. Click parks_polygon and clickAdd.
The dialog box displays the coordinate system, and you
can see it’s the correct one: Transverse_Mercator.
9. Click OK to close the dialog box.
10. Click OK.
11. Click Close to close the Project dialog box.
The Project tool projects the river shapefile to match the
coordinate system of the data in the city’s database. The
projected shapefile, river02prj, is saved in the City_share
folder.
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Exporting the river shapefile to the geodatabase
The projected river dataset will eventually go into the city’s
geodatabase. You’ll export the dataset to a feature class in
the WaterProject geodatabase now, so it will be in the right
format to be copied into the city’s geodatabase later.
1. In the Catalog tree, navigate to the City_share folder,
right-click river02prj, point to Export, and click To
Geodatabase (multiple).
The Feature Class to Geodatabase (multiple) dialog box
appears.
2. Click the Output Geodatabase browse button and
navigate to your project folder.
3. Click WaterProject.mdb and click Add.
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4. Click OK.
A dialog box appears showing the script’s progress.
5. Click Close when the script finishes.
6. Navigate to the WaterProject database and double-click
to display its contents.
7. Right-click river02prj and click Rename.
8. Type “river03exp” and press Enter.
The next task is to update the parks layer with the new
historic park.
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Digitizing the historic park
You need to add the new historic park to the parks layer so
you can include it in the buffer around parks you’ll create
during the analysis. The Parks Department has not yet
added the planned Homestead Historic Park to the parks
feature class in the city’s database, though it has settled on
the boundary. You’ll digitize the park boundary from a
scanned image of the boundary drawn on a map.
You’ll digitize the new park into the copy of the parks
feature class in the WaterProject geodatabase. The updated
file will replace the original file in the city’s database later,
after the Parks Department checks to make sure the new
park was added correctly.
After opening a new map in which to do the digitizing, you’ll
register the scanned image to the streets layer. You’ll then
digitize the park boundary and add the attributes for the
new park.
Opening a new map
You’ll digitize the new park in a new map in ArcMap. You’ll
need to add four datasets to the map: the existing parks
feature class that you’ll be adding the new park to; the
scanned image of the park boundary (stored as a TIFF file),
which you’ll use as a guide while digitizing; the streets layer
that you’ll use to register the scanned image; and the
parcel_2 shapefile that you’ll use to snap the park boundary
to since the boundary aligns with the parcel boundaries.
1. Click the Launch ArcMap button on the ArcCatalog
toolbar.
If the ArcMap startup dialog box appears, click the
option for A new empty map and click OK.
Arrange ArcMap and ArcCatalog so you can see both.
2. In ArcCatalog, navigate to the WaterProject
geodatabase under the project folder connection and
open it by double-clicking it or clicking the plus sign next
to it, if necessary.
3. Click and drag parks_polygon onto the map in ArcMap.
4. Add the parcel_2 shapefile to the map by opening the
City_share\land folder inArcCatalog, clicking parcel_2,
and dragging it onto the map.
The parks_polygon and parcel_2 layers are displayed on
the map.
5. Click the Full Extent button on the Tools toolbar to see
all of both layers.
6. Add the streets layer to the map by opening the
City_layers folder, clicking streets, and dragging it onto
the map.
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7. Now open the City_share\image folder and click and
drag historic onto the map.
You get a warning that the layer is missing spatial reference
information—its coordinate system is undefined.
That’s OK because you’ll be registering the image
interactively to place it in the correct geographic space.
Click OK to close the warning message.
You’ll notice that the image is not displayed even though it
has been added to the map. That’s because it’s in scanner
units (inches) rather than in geographic coordinates.
8. Click the Full Extent button on the Tools toolbar.
When the map redraws, you can see the city data layers as
a small dot in the upper center of the view. The scanned
image is actually drawn in the lower center, but it’s too
small to even see. You saw a similar situation in Chapter 5,
‘Assembling the database’, when you first added the
lowland shapefile to the map.
The extent of the image, which is in inches, is 0 to about 13
in both the x and y directions. The extent of the other data,
which is actual geographic space represented in UTM
meters, is from about 478,000 to about 490,000 in the
x direction and about 3,765,000 to 3,772,000 in the
y direction. ArcMap attempts to draw all the data on the
same page, so the page extent ranges from values of 0,0 in
the lower left of the page to values of more than 490,000 in
the x direction and more than 3,772,000 in the y direction.
The image and the data are drawn in their respective parts
of the page and end up being very small. You need to
register the image so it is in the same geographic space as
the streets, parcels, and parks.
9. Right-click historic.tif in the ArcMap table of contents
and click Zoom To Layer.
Now you can see the image.
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Before registering the image, save the map in case you
need to stop or take a break during the process.
10. Click File and click Save.
11. Navigate to the project folder. Type “water project” to
name the map and click Save.
You’ll use this map for the rest of the project.
Finding the park area on the streets layer
The Parks Department added several registration marks to
the sketch at street intersections. You’ll register the image
to the streets by interactively adding links between the
image and the streets layer—first pointing at a registration
mark on the image, then at the corresponding intersection
on the streets layer. You’ll need to find the area on the
streets layer corresponding to the area covered by the
image. To make it easier to do this, you’ll first open an
overview window, so you’ll be able to see the image and
the streets at the same time.
1. Click Window and click Overview.
A small window appears showing the image.
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The overview window displays whichever layers are
displayed in the main window at the time you open it,
although you can modify this once the window is created.
By default, it also shades the area visible on the main
screen. Since the main window and overview window show
the same area at this point, the shading covers the entire
image in the overview window. When you zoom to the
streets, the overview window will continue to display the
image, so you’ll be able to see both.
Now you can find the park area on the streets layer and
zoom to it.
The image has several streets marked on it in the vicinity of
the park including Robin Lane, Peacock Lane, and Sparrow
Drive. You can search for one of these on the streets layer
to find the area the park is in.
2. Click the Edit menu and click Find.
3. In the Find text box, type “Peacock”.
4. Click the In dropdown arrow, scroll down, and click
streets.
5. Click In fields, click the dropdown arrow, and click
NAME.
6. Click Find.
Peacock appears in the list of features that have been
found.
7. Right-click Peacock and click Zoom to feature(s).
The map displays the area that includes Peacock Lane. The
overview window still displays the image. You may want to
enlarge the overview window so it’s easier to see the
image—simply click and drag one of the corners of the
window. You may also want to move the overview window
to make it easier to see the streets.
5
3
4
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8. Click Cancel to close the Find dialog box.
To make sure you’re in the right area, label the streets.
9. In the table of contents, right-click streets and click
Label Features.
You can see that you’re in the area that includes the park.
10. Use the Zoom In tool on the Tools toolbar to draw a box
around the four street intersections that correspond to
the control points on the scanned image. Use the image
displayed in the overview window to orient yourself.
11. Close the overview window.
Now the display is zoomed to the area corresponding to
the image.
12. You won’t need to display parcel_2 for the next set of
steps, so uncheck the layer to make it easier to see the
streets.
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Registering the scanned image
Now you’re ready to register the image to the streets layer.
You’ll do this by adding links between the control points on
the image and the corresponding street intersections on the
streets layer. This is known as georeferencing. ArcMap
requires a minimum of three links to transform the image—
rotating, scaling, and warping it as needed to fully register it
to the streets.
1. Click the View menu, point to Toolbars, and click
Georeferencing.
The Georeferencing toolbar appears.
2. Click the Layer dropdown arrow and click historic.tif.
3. Click the Georeferencing dropdown arrow and click Fit
To Display.
ArcMap scales the image to fit in the current window.
Since the window is currently zoomed to the four street
intersections that match the registration marks on the
image, the streets and the image are displayed at
approximately the same scale. You can see, though, that the
control points aren’t located exactly at the intersections.
You’ll add three links to register the image. To make it
easier, you’ll use a magnifier window. You can add control
points within the magnifier window.
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4. ClickWindow and click Magnifier.
A small window appears with a default magnification of
400 percent.
When you drag the window and release the mouse button, it
magnifies the portion of the display it is currently on top of
by 400 percent.
5. Click theAdd Control Points button on the
Georeferencing toolbar.
The mouse pointer turns into a crosshair when it is
anywhere on the map.
6. Drag and center the magnifier window over the
registration mark in the upper right, labeled 602, and
release the mouse button. If necessary, reposition the
window so you can see both the registration mark and
the corresponding street intersection—Robin and
Sparrow—within the window.
Note that the registration mark and intersection may be in
slightly different positions on your map.
7. Center the crosshair over the registration mark and
click.
A green control point is added to the image. Move the
mouse pointer away from the control point but don’t
click again.
A line stretches from the control point as you move the
mouse pointer. This is the link—you’ll connect the other
end of it to the corresponding street intersection.Add Control Points
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8. Center the mouse pointer over the intersection of Robin
and Sparrow on the streets layer—you can see the link
stretch as you do this—and click.
You’ve added the other end of the link. The second control
point is shown as a red crosshair. The image is now shifted
so the upper-right corner of the image is in the correct
location—at the corner of Robin and Sparrow. However,
not all registration marks are located exactly at the
intersections. You’ll add a couple more links to achieve
better registration.
Before you add the next link, look at the link table.
9. Click the View Link Table button on the Georeferencing
toolbar.
For each link, the table lists the x and y coordinates for the
source—the scanned image—and the corresponding
coordinates for the map—the streets layer.
If you make a mistake and need to delete a link, select it
and click the Delete button, which looks like the letter X.
10. Click OK to close the Link Table.
Now you’ll add the other two links.
11. Drag and center the magnifier window over the
registration mark in the upper left, labeled 601, and
release the mouse button.
Then click here.
Click here
View Link Table
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138 GETTING STARTED WITH ARCGIS
If necessary, reposition the window so you can see both the
registration mark on the image and the corresponding street
intersection.
12. Center the crosshair over the registration mark and
click.
13. Center the crosshair over the intersection and click to
add the second control point.
The image adjusts slightly. Now add the third link in the
same manner.
14. Drag the magnifier window over the registration mark in
the lower right, labeled 473.
15. Click the registration mark, then click the intersection.
The image shifts again.
Now the control points match closely with the intersections.
You could add a fourth link, but at this point the registration
is acceptable for your purposes.
16. Click the Georeferencing dropdown arrow and click
Update Georeferencing to save the new registration.
You don’t need the control points anymore.
17. Click the Georeferencing dropdown arrow and click
Delete Control Points. Then close the Georeferencing
toolbar.
Keep the magnifier window open since you may want to
use it when digitizing the park boundary.
Then click
here.
Click here
first.
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Displaying the park boundary and the parcels
You need to be able to see the image underneath the
parcels when digitizing, so you’ll draw the parcel outlines.
1. Click the legend symbol under parcel_2 in the table of
contents.
2. In the Options panel on the Symbol Selector dialog box,
click the Fill Color dropdown arrow and click No Color.
3. Click the Outline Color dropdown arrow and set the
color to red.
4. Click OK.
5. Check the box next to the parcel_2 layer to draw the
parcels.
You don’t need to display the streets or the street names at
this point, but you’ll keep the layer on the map for use in the
analysis phase of the project.
6. Right-click streets in the table of contents and click
Label Features—it’s currently checked—to turn off the
street name labels.
7. Uncheck the streets layer so the streets are no longer
displayed.
8. Right-click the historic.tif layer and click Zoom To
Layer.
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Now your display should show only the parcel
boundaries in red on top of the image.
9. Click File and click Save to save your map.
You can see that the parcel boundaries in the parcel_2 layer
match well—but not exactly—with the parcel boundaries on
the image. Since you’ll be snapping the boundary to the
parcel_2 layer and using the image merely as a guide for
digitizing the park boundary, this registration is acceptable.
If you were digitizing solely by tracing from the image, you
would want to make sure the image was as closely
registered to the streets as possible. To do this, you could
add more links. In any case, the registration might never be
exact because of such factors as distortion on the scanned
image, the placement of registration marks on the image,
and slight differences in the location of the streets on the
image—created from a paper map—and in the GIS
database.
Preparing to digitize the park boundary
You’ll align the park boundary exactly with the surveyed
parcel boundaries by snapping to the parcel_2 layer. First
you need to set up the digitizing environment.
1. Zoom in to the park by using the Zoom In tool on the
Tools toolbar to draw a box around the park boundary.
While you’re here, add a bookmark to use when you start
digitizing the boundary.
2. Click the View menu, point to Bookmarks, and click
Create. Name the bookmark Park Boundary and click
OK.
3. Click the Editor Toolbar button.
Editor
Toolbar
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4. Click Editor and click Start Editing.
The Start Editing dialog box appears. You’ll be adding a
feature to the parks_polygon feature class you copied to
the WaterProject geodatabase, so select it as the
database to edit data from.
5. Click project\WaterProject.mdb, then click OK.
The Editor toolbar shows that the target layer—the one
you are editing—is parks_polygon and the current
editing task is Create New Feature.
Now set the snapping environment so the new park
boundary will align exactly with the existing parcel
boundaries.
6. Click Editor, then click Snapping.
7. Check the box in the Vertex column for the parcel_2
layer.
This will snap the editing mouse pointer to the vertices of
the parcels.
8. Close the Snapping Environment dialog box.
The snapping tolerance defines how close the mouse
pointer must be to an object before it snaps to that object.
You can change the snapping tolerance by choosing Options
from the Editor menu. For this exercise you don’t need to
change the snapping tolerance.
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Starting to digitize the boundary
1. Click the Sketch tool.
It may help if you zoom in to the northeast corner of the
park—you can use the Pan and Zoom tools while you are
digitizing. Just click the Zoom tool, drag a rectangle around
the area you want to see, and click the Create New
Feature tool again to resume digitizing. Then use the
bookmark you created to display the full park boundary
again. Or, use the magnifier window. You can move the
window—and move the mouse pointer in and out of the
window—while digitizing.
If you make a mistake while digitizing, click the Undo
button on the ArcMap Standard toolbar.
2. Move the editing mouse pointer over the northeast
corner of the Homestead Historic Park boundary.
The existing parcel boundaries are drawn with red lines,
and the park boundary is drawn with a heavy black line.
You’ll snap to the existing parcel boundary. The digitizing
mouse pointer is shown as a blue dot with a crosshair.
When the mouse pointer gets within the snapping tolerance
of the parcel corner, the blue dot snaps to the vertex.
3. Click the northeast corner of the park to start your edit
sketch.
4. Move the mouse pointer to the southeast corner of the
park. There are two vertices here. Make sure that the
mouse pointer snaps to the southernmost vertex. Click
the vertex.
After you add the second point, a line is drawn back to
the first point in your sketch to create a polygon that
stretches as you move the mouse pointer.
Sketch tool
Undo
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5. Move the mouse pointer to the southwest corner of the
park. There are two vertices here. Click the
southernmost vertex.
Placing a vertex by angle and distance
The next segment of the park boundary is only half as long
as the parcel boundary. The scanned image includes
dimensions for each segment. You’ll use the dimensions to
place the next two vertices using angle and distance.
1. Place the mouse pointer near the parcel boundary line at
the corner of the park. Right-click and click Parallel.
Now the mouse pointer is constrained to be parallel to the
parcel boundary.
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2. Right-click again and click Direction/Length.
The Direction/Length dialog box appears.
3. Click in the Direction text box and type “90”, then click
in the Length text box and type “98”. Press Enter.
The length of this segment of the park boundary as
shown on the image is 98 meters.
A vertex is placed on the line coinciding with the parcel
boundary 98 meters from the previous vertex you added
at the corner of the parcel.
4. Move the editing pointer near the midpoint of the north
boundary of the parcel. Right-click and click Parallel.
Now the next segment you add will be parallel to the north
boundary of the parcel.
5. Right-click again and click Direction/Length.
3
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6. Click in the Direction text box and type “360”, then click
in the Length text box, type “100.5”, and press Enter.
The new segment is added to the edit sketch; it is
100.5 meters long and parallel to the north boundary of
the parcel.
Adding a perpendicular line
The next segment is perpendicular to the segment you just
added.
1. Move the mouse pointer along the vertical line, partway
to the north boundary of the parcel, right-click, and click
Perpendicular.
Now the mouse pointer is constrained to be
perpendicular to the previous segment.
5
6
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2. Click to add a vertex partway to the north boundary.
Adding a point at the intersection of lines
1. Click the Create New Feature tool dropdown arrow and
click the Intersection tool.
The Intersection tool lets you place the next point in your
edit sketch at the intersection of two lines.
2. Place the mouse pointer near the segment you just
created. A temporary line extends along the segment.
You will make this the first intersection line. Click to set
the intersection line.
3. Place the mouse pointer near the north boundary of the
parcel. You will make this the second intersection line.
Click to set the intersection line.
First intersection
line
Intersection Second
intersection line
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The new vertex appears at the intersection of the two
lines at the corner of the boundary.
Finishing digitizing
1. Click the northeast corner of the park, right-click, then
click Finish Sketch.
The new park polygon is finished. Its boundary turns
light blue to indicate that it is selected, and it takes on the
color of the other park polygons.
2. Close the magnifier window if it’s still open.
Editing the feature attributes
Now that you’ve finished digitizing the park, you can update
the new feature’s attributes in the database.
1. Click the Attributes button on the Editor toolbar.
Attributes
Vertex added at
intersection
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2. Click next to Name in the Value column and type
“Homestead Historic”.
The park will be maintained by the city, so you will update
the maintenance field as well.
3. Type “City” as the value for the Maintenance field and
press Enter. Close the Attributes dialog box.
4. Right-click parks_polygon in the table of contents and
click Label Features.
The new park is labeled with its name.
2
3
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Saving your edits
Now save your changes to the park feature class in the
database.
1. Click Editor, then click Save Edits.
2. Click Editor, then click Stop Editing.
Although this was a simple example, you saw how the
Editor provides a variety of tools for constructing features.
Before continuing, clean up the table of contents. You don’t
need the historic.tif layer anymore, so remove it from the
map.
3. Right-click historic.tif in the table of contents and click
Remove.
4. You don’t need to display parks right now, so uncheck
them.
5. Click File and click Save to save your map at this point.
The last task before you start the analysis is to merge the
two parcel layers.
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Merging the parcel layers
Sometimes data that you need is in two or more adjacent
datasets, either because of the way the data was created or
the way it is stored. For example, multiple datasets might be
created by digitizing from adjacent map sheets into separate
shapefiles. In some cases, data for large areas is stored as
sets of separate tiles to make it easier to manage and
update the features.
The parcel data that you will use in the analysis is stored as
tiles of adjacent shapefiles. You have two tiles that you will
merge into a single layer, so you’ll be able to more easily
select the suitable parcels during the analysis.
In order to merge the two adjacent layers, you will create a
new feature class in the WaterProject geodatabase, then
load both existing parcel layers into the new feature class
layer.
Creating the new feature class
1. Right-click parcel_2 and click Zoom To Layer.
Now you’ll add the other parcel layer to the map.
2. Click the Add Data button, navigate to the
City_share\land folder under the project folder, click
parcel_1, and click Add.
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You can see the two adjacent parcel layers. Parcel_1 is
drawn with a default solid fill color, while the parcel_2
boundaries are displayed in red.
3. Make sure ArcCatalog is open, then right-click the
WaterProject geodatabase in ArcCatalog, point to New,
and click Feature Class.
4. Type “parcel01mrg” as the name, click Next, then click
Next again.
5. Click Geometry under Data Type and confirm that the
Geometry data type under Field Properties is Polygon. If
it isn’t Polygon, click in the box, click the dropdown
arrow that appears, and click Polygon.
6. Click the ellipsis (...) button next to the Spatial
Reference text box.
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The Spatial Reference Properties dialog box appears.
7. Click Import on the Spatial Reference Properties dialog
box to import a coordinate system from an existing
geodatabase.
The spatial extent of the coordinate system imported to
create the new feature class must include all data that
will be loaded. Since the spatial extent of parcel_2
encompasses parcel_1, parcel_2 will be used as the
input coordinate system reference for this new feature
class.
8. Select parcel_2 from the City_share\land folder, then
clickAdd.
The Spatial Reference Properties dialog box displays
with the coordinate system of parcel_2.
9. Click Apply and click OK.
10. Click the Import button on the New Feature Class dialog
box. This imports the fields from an existing feature
class.
11. Select parcel_2 from the City_share\land project folder,
clickAdd, then click Finish.
Parcel01mrg is added as a new Personal Geodatabase
Feature Class.
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Loading parcel_1 data
The new feature class has now been created using the
spatial extent and field names of parcel_2, but it’s still
empty. You need to load both the parcel_1 and parcel_2
shapefiles to create the final merged feature class.
1. Right-click parcel01mrg inArcCatalog, point to Load,
and click Load Data.
2. Click Next on the Simple Data Loader dialog box.
3. Click the Browse button next to the Input data field,
select parcel_1 from the project\City_share\land folder,
then click Open.
4. Click Add, click Next, then click Next again.
The data loader attempts to match the source field
(parcel_1) to the target field (set by parcel_2). Since the
field names for the new feature class were created
based on parcel_2, you need to specify the fields in
parcel_1 that represent the same data but have a
different name.
5. Click the first box labeled None under the Matching
Source Field. Click Parcel_1_[double] in the dropdown
box that appears.
6. Click the box labeled None directly below, then click
PARCEL_1_l[double] from the dropdown menu.
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154 GETTING STARTED WITH ARCGIS
7. Click Next, click Next again, then click Finish.
Next you will repeat this process to add parcel_2 to the
parcel01mrg feature class.
Loading parcel_2 data
1. Right-click Parcel01mrg, point to Load, then click Load
Data.
2. Click Next on the Simple Data Loader dialog box.
3. Click the Browse button next to the Input data field,
click parcel_2 from the project\City_share\land folder,
then click Open.
4. ClickAdd, click Next, then click Next again.
This time, the Matching Source Field contents are
already filled in because you used parcel_2 as the
template for this feature class.
5. Click Next, click Next again, then click Finish.
Click the Preview tab for the parcel01mrg feature class,
and you will see that both parcels have been combined
to form a single feature class.
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PREPARING DATA FOR ANALYSIS 155
6. Click and drag the new parcel01mrg feature class from
ArcCatalog to the top of the table of contents in your
map.
7. You don’t need the parcel_1 and parcel_2 layers any
longer, so remove them from the map by right-clicking
them and clicking Remove.
8. Click File and click Save to save your map.
In this chapter you have prepared your data for the analysis
and completed the project database. Preparing data—
whether by converting it, changing its coordinate system,
managing its attributes, or editing its features—is an
important part of a GIS project. The quality of the analysis
and map depends on the quality of the data. An
organization’s biggest investment in a GIS project, other
than its staff, is usually in its data.
In the next chapter you’ll perform the analysis to find
parcels that meet the city’s criteria as a site for the
wastewater treatment plant.
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IN THIS CHAPTER
157
Performing the analysis
7
• Setting up for analysis
• Delineating the area the plant site
should be within
• Delineating the areas the plant site
should be outside of
• Finding the parcels that meet the
location criteria
• Finding the vacant parcels
• Finding suitable parcels near
roads and near the wastewater
junction
• Finding suitable parcels meeting
the required total area
• Reviewing the analysis results
In the planning phase you decided which data you would need in order to
meet the criteria. You then assembled the data and prepared it for analysis.
At this point you’re ready to perform the analysis.
There are often several alternative methods you can use to get to the end
result. The approach you use is partly dictated by the problem you’re trying
to solve, partly by the data you’re using, and partly by personal preference.
In this analysis, the parcels suitable for a site for the wastewater treatment
plant have to meet certain location criteria and also have to be vacant.
The location criteria fall into two categories: features the plant should be
away from or outside of—away from parks and residences, outside the
flood zone—and features the plant should be near or inside of—near the
river, inside the low elevation area. The areas delineated by these criteria
become the unacceptable and acceptable areas for the plant, respectively.
You’ll find the parcels that fall outside the unacceptable areas, then find the
subset of these that fall inside the acceptable areas. Next, of the remaining
parcels, you’ll find the ones that are vacant.
The city also prefers that the site be near a road and near the existing
wastewater junction. You’ll find and tag the parcels that are within
50 meters of a road. You will also find and tag the parcels that are within
500 and 1,000 meters of the wastewater junction. Finally, you’ll find parcels
that are at least 150,000 square meters in size, large enough to build the
plant on.
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158 GETTING STARTED WITH ARCGIS
Setting up for analysis
If you closed ArcCatalog and ArcMap at the end of
Chapter 6, ‘Preparing data for analysis’, you’ll need to
reopen them and reopen the water project map. Your map
should currently include the parks_polygon, streets, and
parcel01mrg layers, with the parcels displayed.
You’ll be adding data from several locations during the
analysis, so in the Catalog tree navigate to and open the
project folder so you can see the City_layers, City_share,
and State_share subfolders and the WaterProject
geodatabase. Open each subfolder and the geodatabase so
you can see the contents of each.
Now you’re ready to start the analysis process. The
general approach for this analysis was presented in the
flowchart in Chapter 4, ‘Planning a GIS project’. At this
point, you need to develop the specific steps for each phase
of the analysis. Detailed flowcharts for each section are
presented at the beginning of the appropriate section in this
chapter. You’ll implement the analysis using ArcMap.
Combining the river buffer and lowland layer and combining
the park and residential buffers with the flood zone layer
will reduce the number of selections you’ll have to do to
find the parcels that meet the criteria. It’s easier to do the
selections all at one time, so you’ll first create the two
layers that delineate the acceptable and unacceptable areas,
then do all three selection steps.
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PERFORMING THE ANALYSIS 159
Delineating the area the plant site should be within
In this phase of the analysis you’ll buffer and combine
features to delineate the areas the wastewater treatment
plant should be within—areas within 1,000 meters of the
river and lowland areas. You’ll create a 1,000-meter buffer
around the river, then combine the buffer with the lowland
layer. Here are the steps:
• Create a 1,000-meter buffer around the river.
• Overlay the river buffer and the lowland layer.
Here’s a flowchart of the process using the layer names:
Buffering the river
You’ll use the Buffer tool in ArcToolbox to buffer
river03exp to 1,000 m to create river04buf. The Buffer tool
is one of many geoprocessing tools contained in
ArcToolbox. Any of the geoprocessing tools can be run
fromArcToolbox, from the command line, through the
ModelBuilder™, or with a Script. These options will be
described in more detail throughout this section. If you
would like more information on geoprocessing methods
after working through this tutorial, see Geoprocessing in
ArcGIS.
1. Uncheck the parcel01mrg layer since you won’t need to
display it until later.
2. In the Catalog tree, click river03exp in the WaterProject
geodatabase and drag it onto the map in ArcMap.
3. Click the Full Extent button on the Tools toolbar to see
the river.
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160 GETTING STARTED WITH ARCGIS
4. Click the Show/HideArcToolbox button on the Standard
toolbar.
5. Double-clickAnalysis Tools in theArcToolbox tree,
double-click Proximity, then double-click the Buffer tool.
The Buffer dialog box appears.
6. Click the Input Features browse button, navigate to and
double-click WaterProject.mdb in the project folder, click
river03exp, and clickAdd.
7. In the Output Feature Class box type the path to the
Analysis folder, and type “river04buf.shp” as the layer
name.
For the rest of the analysis, the output layers you create
will be shapefiles in the Analysis folder.
8. Type “1000” in the Linear unit field and click the
dropdown menu to change from Unknown units to
Meters to create a buffer of 1,000 meters around the
river.
9. Click the dropdown arrow for Dissolve Type and choose
ALL; the river is actually composed of five line
segments, each of which will be buffered, so dissolving
the barriers will create a single buffer around the river.
Leave the default settings for Side Type and End Type.
10. Click OK.
The Buffer window appears automatically, and the
buffer is created.
11. Close the Buffer window. The river04buf layer appears
on your map. (If it didn’t, click Tools, Options, then the
Geoprocessing tab and check the box to add results to
the display.)
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12. Drag the river03exp layer above the river04buf layer in
the table of contents to display it on top.
Overlaying the river buffer and the lowland area
Next you’ll use the Intersect tool to combine the lowland
layer and the river buffer to create low_river, which
delineates the area the plant site needs to be within.
1. Add the lowland shapefile to the map by dragging it from
the State_share folder in the Catalog tree.
ArcMap warns you that the lowland shapefile is in a
different coordinate system than the other data on the
map. That’s okay—since you’ve defined the coordinate
system for lowland (in Chapter 6, ‘Preparing data for
analysis’), it will overlay correctly with the other data.
Click OK to close the Warning message box.
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162 GETTING STARTED WITH ARCGIS
2. Double-click the Intersect tool under Overlay in the
Analysis Tools.
The Intersect dialog box opens.
3. Click the Browse button on the Input Features box,
navigate to lowland, and click Add. Do the same for
river04buf.shp.
4. In the Output Feature Class box, ensure the path to the
Analysis folder is displayed and type “low_river” as the
layer name. If the path to the Analysis folder is not
displayed, type it in or use the Browse button to navigate
to it, then type the name of the new layer.
5. Click the JoinAttributes dropdown arrow and click ALL.
6. Leave the remaining fields as default and click OK.
7. When the intersect is complete, close the Intersect
window. Drag low_river from the Analysis folder to the
top of the map’s table of contents. It’s okay if you get a
coordinate system warning message.
The new layer is displayed. It contains only the area
covered by both the river buffer and the lowland layer.
You can see the lowland and river buffer layers
underneath and that the new layer, low_river, represents
the intersection of the two.
8. Uncheck low_river, river03exp, lowland, and river04buf
since you don’t need to display them for the next step.
Keep them on the map, though, since you may want to
use them later to verify the results of your analysis.
9. Click File and click Save to save your map.
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Delineating the areas the plant site should be outside of
Now you’ll find the areas the plant should be outside of—
areas within 150 meters of parks and residential parcels and
within the flood zone. You’ll create a 150-meter buffer
around parks, then select the residential parcels from the
parcel layer and create a 150-meter buffer around them.
You’ll then combine the two buffer layers and combine the
result with the flood zone layer. The resulting layer will
delineate the areas the plant site should not be within.
Here’s a flowchart of the process:
Here are the steps:
• Buffer the parks to 150 meters.
• Select the residential parcels.
• Buffer the residential parcels to 150 meters.
• Overlay the parks and residential buffers.
• Overlay the combined park and residential buffer layer
with the flood zone layer.
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164 GETTING STARTED WITH ARCGIS
Buffering the parks
First you’ll create a 150-meter buffer around parks.
1. Check parks_polygon in the table of contents to display
the parks.
The parks are labeled with their names.
2. Right-click parks_polygon and click Label Features,
which is currently checked on, to turn off the labels.
You will use the Command Line to buffer the parks in
this section.
3. Click the Show/Hide Command Line button on the
toolbar in ArcMap if the Command Line window isn’t
already open.
4. The Command Line window appears in the ArcMap
document. Click and drag the bar at the top of the
Command Line window to the bottom of the document
so it’s displayed horizontally.
5. Click in the top of the Command Line window and type
“Buffer”. Buffer is highlighted. Since this is what you
want, press the spacebar. The command line usage for
Buffer appears.
6. Begin typing “parks_polygon” and it will be
automatically selected from the dropdown list. Press the
spacebar, and parks_polygon will be added to the
command line.
You must next specify the out_feature_class, the name,
and directory of the new file you are creating.
7. Type “c:\project\Analysis\park02buf” and press the
spacebar. If your project folder is on a drive other than
C, type the drive where your project is located.
8. Type “150” for the buffer distance and press the
spacebar.
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PERFORMING THE ANALYSIS 165
Selecting the residential parcels
Previously, you created buffers for a layer with a single
feature (the river) and a layer with many features (parks).
This time you’ll buffer selected features in a layer—only
the residential parcels from the parcel01mrg layer. You
need to know the land use code for residential parcels so
you can select them. You can get the code from the
metadata.
1. In ArcCatalog, click parcel_1 in the City_share\land
folder and click the Metadata tab.
2. Click the Stylesheet dropdown arrow and click FGDC
FAQ.
The format of the metadata changes.
9. Specify FULL for line_side, ROUND for line_end_type,
and ALL for dissolve_option, pressing the spacebar to
move between each command.
You don’t need to specify the dissolve field at this time.
10. Press Enter to run the command.
The park buffers are automatically added to the map
document.
11. Close the Command Line window.
12. Drag the parks_polygon layer above the park02buf
layer in the table of contents to display it.
2
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166 GETTING STARTED WITH ARCGIS
The metadata that you see displayed in Catalog is controlled
by the stylesheet that you use to display it. The stylesheets
are similar to database queries—they basically define what
information is pulled out of the metadata and how it can be
formatted.
ArcGIS provides several predefined stylesheets—the
default is the ESRI stylesheet, which you used earlier. You
can also create your own stylesheets.
The FGDC FAQ stylesheet was developed by the Federal
Geographic Data Committee to present the metadata in the
form of a set of frequently asked questions. This format lets
you see the values for each attribute in a layer (as long as
they’ve been defined in the metadata).
3. Click “7. How does the data set describe geographic
features?” in the first section.
The value definitions for the land use attribute are listed
(you may need to scroll down to see them). You can see
that residential parcels have a value of 510. Note also
that vacant parcels have values of 713, 723, and 732.
You’ll use these values later in the analysis.
Before selecting the residential parcels, zoom in to the
parcel layer.
3
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PERFORMING THE ANALYSIS 167
4. Right-click parcel01mrg in the ArcMap table of contents
and click Zoom To Layer, then check the layer to display
the parcels.
You can also see the buffer around the historic park.
5. Click the Selection menu and click Select By Attributes.
6. In the Select By Attributes dialog box, click the
dropdown arrow next to the Layer box and click
Parcel01mrg as the layer to select from.
The default method is to Create a new selection, which is
what you want.
You’ll use the query builder to create a simple query
expression.
7. Double-click LANDUSE in the Fields list.
8. Click the equals sign (=) button.
9. Click Get Unique Values and double-click 510 (the code
for residential) in the Unique Values list.
6
7
8
9
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168 GETTING STARTED WITH ARCGIS
You can see the query expression you’ve built in the text
box. It should look like this:
[LANDUSE] = 510
10. ClickApply. The residential parcels are highlighted with
a blue line. Close the Select By Attributes dialog box.
Now you’ll be able to create buffers around the parcels to
keep the plant from being sited too close to a residence.
Buffering the selected parcels
To complete the buffer of the selected parcels and overlay
of the park and residential buffers, you will create a
graphical model in ModelBuilder, another option for
geoprocessing inArcGIS.
Models automate the process of performing a sequence of
geoprocessing tasks on your data. You can run a model
over and over with a single click, so you can quickly change
parameter values to experiment with different outcomes.
You can also export a model you have created to a script,
enabling you to easily create new scripts that you can then
modify.
Although models can be built with several operations, then
run at the end, you will create the model in several steps,
running each process individually, enabling you to examine
the results of each processing step.
1. Make sure the ArcToolbox window is open in your map
document. If not, click the Show/Hide ArcToolbox
button on the Standard toolbar.
2. Right-click theArcToolbox folder and click New
Toolbox.
3. Right-click the new toolbox that is added and click
Rename. Type “My Tools” as the new toolbox name and
press Enter.
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PERFORMING THE ANALYSIS 169
4. Right-click My Tools, point to New, and click Model.
A new ModelBuilder window opens, allowing you to
start building your model.
The toolbar gives you quick access to much of the
available functionality in the ModelBuilder menus and
more.
There are multiple ways to add data and tools to a
model. Click the Add Data or Tools button and add data,
or drag input data from the ArcCatalog tree or layers
from the table of contents of any ArcGIS Desktop
application having a display.Alternatively, supply the
input data parameter values inside the tool’s dialog box.
5. Click and drag parcel01mrg from the table of contents
and drop in the ModelBuilder window. Parcel01mrg is
automatically displayed as a blue oval, indicating that it is
an input variable. Drag the oval to the left side of the
window.
6. Double-clickAnalysis Tools inArcToolbox, double-click
Proximity, and drag and drop the Buffer tool in the
ModelBuilder window.
When you add the Buffer tool, it automatically creates a
derived data element—in this case the Output Feature
Class. Both the tool and derived data elements stay
white, indicating that the tool is in a not-ready-to-run
state until it is connected to input data.
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170 GETTING STARTED WITH ARCGIS
7. Click theAdd Connection button on the Model toolbar.
8. Click and drag a line from parcel01mrg to the Buffer
tool. All model elements should now be shown in color.
The input element is displayed in a blue oval, the tool is
displayed in a yellow rectangle, and the output element is
displayed in a green oval.
9. Double-click the Buffer tool in the model. The Buffer
tool dialog box appears. The Input Features box is
already filled in for you.
10. In the Output Feature Class text box, type or browse to
the path to the Analysis folder and type “res01buf.shp”
as the layer name.
11. Type “150” in the Linear unit field and click the units
dropdown menu to change from Unknown to Meters.
12. Click the dropdown arrow for Dissolve Type and click
ALL, then click OK.
13. Click the Model dropdown menu on the toolbar and click
Run.
The Buffer tool will flash red while processing. The
Buffer tool and res01buf.shp output element now have
drop shadows, indicating that the process has run and
the derived data has been generated.
The geoprocessing window will appear automatically in
ArcMap and display a log of the processes that have
been run. Close it when it’s finished.
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14. Right-click the res01buf.shp data element and click Add
To Display.
The selected parcels and their buffers are displayed.
Now that you have built the first part of your model, it is
a good idea to rename it to reflect its contents. It is also
good practice to save the model as you are building it.
15. Click the Model menu and click Model Properties.
The Model Properties dialog box opens.
16. Click the General tab and type “Site_Analysis” in the
Name text box and “Site Analysis” in the Label text box,
then click OK.
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17. Click the Model menu and click Save.
Site Analysis is now saved as the name of the model in
My Tools and as the label for the ModelBuilder window.
Overlaying the park and residential buffers
Now you’ll combine the park and residential buffers to
delineate the areas within 150 meters of a park or
residence. To do this, you will add to your existing Site
Analysis model using the Union tool.
1. Click and drag park02buf from the table of contents to
the ModelBuilder window and place directly below the
res01buf data element. Expand your ModelBuilder
window as necessary.
2. Double-click the Overlay Tools under theAnalysis
Toolbox. Click and drag the Union tool from the Toolbox
to the ModelBuilder window.
3. Click the Add Connection button on the toolbar to draw a
connection from park02buf to the Union tool and from
res01buf to the Union tool.
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4. Double-click the Union tool. The Union dialog box
appears; the features have already been filled in for you.
5. Ensure the path to your Analysis folder is specified for
the Output Feature Class and specify “respark_buf” as
the output layer name.
6. Click OK.
Another way to run a model process is to click the Run
button on the ModelBuilder toolbar.
7. Click the Run button on the toolbar.
Notice that the model will only run processes that have
not yet been run. When completed, close the Site
Analysis process dialog box.
8. Right-click the respark_buf.shp data element, then click
Add To Display.
9. Save your model.
You have now buffered the selected residential parcels and
overlaid those parcels with the buffered parks using the
Union tool. Next you will overlay the result of the buffered
parcel and park union with the flood zone to delineate all the
areas the wastewater treatment plant should be outside of.
Overlaying the residential/park buffers and flood
zone
1. Click and drag the flood_zone layer, located in the
City_layers folder, from the Catalog tree onto the map.
2. Click and drag the flood_zone layer from the table of
contents to your Site Analysis model and place it directly
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174 GETTING STARTED WITH ARCGIS
below the respark_buf data element, expanding your
ModelBuilder window as necessary.
You’ll use the Union tool again since you want to create a
layer of areas inside either the residential and park buffers,
the flood zone, or both.
3. Click and drag the Union tool from ArcToolbox to your
model. The new tool will be called Union2 since there is
already a Union tool in the model.
4. Click the Add Connection tool and draw a connection
from respark_buf and flood_zone to the Union2 tool.
5. Double-click the Union2 tool. The Union dialog box
appears; the features have been filled in for you.
6. Ensure the path to the Analysis folder is displayed and
type “respark_flood” as the output layer name.
7. Click OK.
8. Click the Run button on the toolbar.
9. Close the Site Analysis process dialog box.
10. Click the Model menu and click Save.
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11. Right-click the respark_flood element in the model and
clickAdd To Display.
12. Turn off all the layers except respark_flood by
unchecking them in the map’s table of contents.
So far you’ve performed a series of buffers and overlays to
create the two layers delineating the acceptable and
unacceptable areas for the wastewater treatment plant site
based on the city’s criteria. You can see that even a fairly
simple GIS analysis consists of stringing together a set of
individual operations, often with the same operation
repeated on different datasets. The operations build on the
previous ones to achieve a resulting layer or layers. In the
process, interim layers are created. You’ll want to keep
some of these layers to help verify the final results of your
analysis. Others you can remove from the map.
13. Click respark_buf in the table of contents to select it,
press the Ctrl key, and click res01buf and park02buf so
all three layers are selected.
14. Right-click one of the selected layers and click Remove.
Before continuing, save your map.
15. Click File and click Save.
In many instances, the geoprocessing work that must be
done is repetitive. Scripts are an efficient and effective way
to automate your geoprocessing tasks.
If you are new to scripting languages, you do not need to be
an expert programmer to create and use scripts. You can
build a model in a ModelBuilder window and export the
model to a script that you can then run or modify.
The following section will guide you through the steps to
create a script from the Site Analysis model you have just
created.
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176 GETTING STARTED WITH ARCGIS
Generating a script from a model
1. Click the Model dropdown menu, point to Export, point to
To Script, then select your preferred scripting
language—for example, Python.
The Save As dialog box appears.
2. Click the Save in dropdown arrow and navigate to your
analysis folder, then type “site_analysis” as the name for
the script and click Save.
Now you will add the script you have just exported to
your My Tools toolbox.
3. Right-click My Tools, point toAdd, then click Script.
The Add Script dialog box appears.
4. Type “Site_Analysis” in the name box and “Site
Analysis” in the label box, then click Next.
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PERFORMING THE ANALYSIS 177
5. Click the Browse button to select a Script File.
6. Navigate to yourAnalysis folder, click site_analysis.py,
and click Open.
7. Click Next, then click Finish. The script is now added to
your My Tools toolbox.
8. Right-click the Site_Analysis script and click Edit.
This opens the Python script in the PythonWin
application so you can view or modify the contents of
the script.
9. Close the Site_Analysis script and PythonWin
application.
10. Your Site Analysis model is now complete, and you have
successfully exported it to a script, so save your model
and close it.
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178 GETTING STARTED WITH ARCGIS
In the next two sections, you’ll use the interim layers
(low_river and respark_flood) in a series of selections to
eliminate the unsuitable parcels, creating a final layer of
suitable parcels. Here’s the flowchart for this process:
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PERFORMING THE ANALYSIS 179
Finding the parcels that meet the location criteria
At this point you have two layers to use to select parcels
meeting the criteria for the wastewater treatment plant site.
First you’ll select parcels falling outside the respark_flood
polygons, then you’ll select the subset of these that fall
inside the low_river polygon.
Selecting the parcels outside the residential/park
buffer and flood zone areas
You’ll use Select By Location to select parcels that
intersect the respark_flood layer. The selected parcels will
lie fully or partially within the flood zone or within a
residential or park buffer. You’ll then switch the selected set
to select the parcels that lie outside those areas. The
selected parcels will be outside the flood zone and more
than 150 meters from a park or residence.
1. Click the check box next to the parcel01mrg layer to
display it.
You can see that some parcels fall within the
respark_flood area.
2. Click Selection and click Select By Location.
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180 GETTING STARTED WITH ARCGIS
The Select By Location dialog box appears. This dialog
box lets you compose a wide variety of queries to select
features in one layer based on their location relative to
features in another layer. In the top box you specify the
type of selection. The default is to create a new selected
set (select features from), which is what you want. In
the next box you choose the layer to select from.
3. Scroll down and click the check box next to
parcel01mrg.
Next, you will specify the relationship between the layers.
The default is intersect—features that fall fully or partially
within the features of the selection layer will be selected.
This is the option you want, so accept the default. Finally,
you specify the selection layer.
4. Click the dropdown arrow and click respark_flood.
5. Click Apply at the bottom of the dialog box, then click
Close to close the Select By Location dialog box.
ArcMap selects the parcels that are completely or
partially within the respark_flood polygons and highlights
them on the map.
You actually want the parcels that are outside the
respark_flood polygons, not inside, so you’ll switch the
selected set of parcels.
6. Right-click parcel01mrg in the table of contents, point to
Selection, and click Switch Selection.
3
4
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PERFORMING THE ANALYSIS 181
Now the parcels outside the flood zone and more than
150 meters from a park or residence are selected.
Selecting those parcels within the combined river
buffer and lowland area
The next step is to select from the currently selected
parcels those that are within the lowland area and within
1,000 meters of the river. You’ll use Select By Location
again, this time to select from the currently selected set of
parcels.
1. Click the check box next to the low_river layer to
display it.
2. Click Selection and click Select By Location.
3. Click the dropdown arrow for the top box and click the
‘select from the currently selected features in’ option.
4. Check the box to select features from parcel01mrg, if
it’s not already checked.
5. Click the dropdown arrow to choose a relationship type
and click ‘have their center in’.
That will select the parcels that have at least half their
area within the low_river polygon.
6. Click the dropdown arrow, scroll down, and click
low_river as the selection layer.
7. Click Apply and click Close to close the Select By
Location dialog box.
4
3
5
6
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182 GETTING STARTED WITH ARCGIS
ArcMap selects those parcels that are mostly within the
low_river polygon. You can see that the selected parcels
are outside the respark_flood area and inside the
low_river area.
So far you’ve narrowed down the set of possibly suitable
parcels from all the parcels in the study area to those
outside the flood zone and more than 150 meters from a
park or residence. You then narrowed the set further to
those parcels with at least half their area inside the lowland
area (elevation 365 meters or less) and within 1,000 meters
of the river. The next step is to find the vacant parcels from
among these.
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PERFORMING THE ANALYSIS 183
Finding the vacant parcels
To find which parcels meet all the city’s requirements as a
location for the wastewater treatment plant, you’ll select
the vacant parcels from among the currently selected ones.
Selecting vacant parcels using the land use code
In the last two selections, you selected parcels based on
their location. This time, you’ll select based on an attribute,
specifically, the parcel land use code. As you recall from
the metadata in the assessor’s database, vacant land is
coded with values in the 700s. You’ll create a query
expression to select the parcels that have a land use code
greater than or equal to 700 and less than or equal to 799.
1. Click Selection and click Select By Attributes.
The Select By Attributes dialog box appears.
2. Click the Layer dropdown arrow and click parcel01mrg.
3. Click the Method dropdown arrow and click Select from
current selection.
Now you’ll create the query expression.
4. Double-click “LANDUSE” in the Fields list.
5. Click the greater than or equal to (>=) sign and type
“700”.
6. ClickAnd.
7. Double-click LANDUSE in the Fields list.
8. Click the less than or equal to (<=) sign and type “799”.
Your query expression should look like this:
[LANDUSE] >= 700 AND [LANDUSE] <= 799
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184 GETTING STARTED WITH ARCGIS
9. ClickApply.
ArcMap selects the parcels that have land use codes in
the 700s (the vacant parcels) and highlights them.
10. Close the Select By Attributes dialog box.
The selected set of parcels contains only the ones that meet
the city’s required criteria:
• Outside the flood zone
• At least 150 meters from parks and residences
• Elevation of 365 meters or less
• Within 1,000 meters of the river
• Vacant
Exporting the selected parcels to a new shapefile
To make it easier to work with only the suitable parcels,
you’ll export the selected parcels to a new shapefile.
1. Right-click parcel01mrg in the table of contents, point to
Data, and click Export Data.
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PERFORMING THE ANALYSIS 185
The Export Data dialog box appears. Since there are
features currently selected in the parcel01mrg layer, the
dialog box defaults to Selected features.
2. Make sure the path to the Analysis folder is displayed in
the output feature class box.
The dialog box defaults the name of the new shapefile to
be Export_Output.shp.
3. Highlight the text and type “parcel02sel” to rename the
feature class.
4. Click OK and click Yes when prompted to add the
exported data to the map.
3
The new layer contains only the suitable parcels.
5. Click Selection and click Clear Selected Features to
deselect the parcels in the parcel01mrg layer.
6. Click File and click Save.
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186 GETTING STARTED WITH ARCGIS
Finding suitable parcels near roads and near the wastewater junction
To continue with the decision-making process of the
location of the wastewater treatment plant, the city council
wants to know which suitable parcels are within 50 meters
of a road and within 500 and 1,000 meters of the main
wastewater junction. These will be considered the highly
suitable parcels.
You’ll select the parcels near these features and tag them
with a code. That way you can display them color coded on
your final map.
Here are the steps you’ll perform:
1. Add two fields to the parcel02sel attribute table to hold
the distance values: ROAD_DIST and JUNC_DIST.
2. Assign distance from roads.
• Select the parcels within 50 meters of a road.
• Assign a value, “50”, to the ROAD_DIST field for
the selected parcels in the parcel02sel attribute table.
3. Assign distance from the wastewater junction.
• Buffer the junction to 500 and 1,000 meters.
• Select the 1,000-meter buffer and use it to select the
parcels within 1,000 meters of the junction.
• Assign a value of 1,000 to the JUNC_DIST field
for the selected parcels in the parcel02sel attribute
table.
• Select the 500-meter buffer and use it to select the
parcels that fall within 500 meters of the junction.
• Assign a value of 500 to the JUNC_DIST field for
the selected parcels.
Here’s the flowchart of the process:
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PERFORMING THE ANALYSIS 187
Adding fields to the parcels layer
Before you find the parcels near roads and the wastewater
junction, you’ll add two fields to the parcel02sel attribute
table to contain the distance values you’ll assign.
1. Right-click parcel02sel and click Open Attribute Table.
2. Click the Options button on the table and click Add Field.
The Add Field dialog box appears.
3. Type “ROAD_DIST” as the field name.
You can accept the default type of short integer.
The short integer type stores values up to 32,768, which
is sufficient for the ROAD_DIST field—the values in
this field will be either 50 or 0.
4. Click OK.
Now add the JUNC_DIST field in the same way.
5. Click Options and clickAdd Field.
6. Type “JUNC_DIST” as the field name and click OK.
7. Scroll all the way to the right of the Attributes dialog box
to see the new fields.
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188 GETTING STARTED WITH ARCGIS
Currently, the two columns have no values in them or
contain zeros, since you just added the fields. In the next
few steps you’ll select the parcels near roads and the
wastewater junction and enter values for the selected
parcels.
8. Close the attribute table for now by clicking the Close
button.
Finding parcels within 50 meters of a road
The city would prefer that the parcel for the new plant be
within 50 meters of an existing road. You’ll use the streets
layer to select the parcels within 50 meters of a road and
assign a value of 50 to the ROAD_DIST field.
1. Before continuing, uncheck the check boxes for all
layers except parcel02sel in the table of contents so that
only the suitable parcels are displayed.
2. Check the streets layer to display it.
3. Click the Selection menu and click Select By Location.
You’ve seen this dialog box before. This time, you’ll
select features on one layer (parcels) within a distance
of features on another layer (streets).
4. Click the ‘I want to’ dropdown menu and click ‘select
features from’.
5. Check the check box for parcel02sel.
6. Click the dropdown arrows for the next two text boxes
and click ‘are within a distance of’ and ‘streets’.
The option to Apply a buffer to the features in streets is
automatically checked.
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PERFORMING THE ANALYSIS 189
Using a buffer when selecting features is an easy way of
finding features within a certain distance of other features.
This method is quicker than using the Buffer tool—as you
did with rivers, parks, and residential parcels—when you
don’t need to create a separate buffer layer to combine
with other layers.
9. Click Close to close the Select By Location dialog box.
Now you can assign a value to the ROAD_DIST field for
the selected parcels to tag them as being within 50 meters
of a road.
Assigning a value to the ROAD_DIST field
To assign or update values in a layer’s attribute table, you
need to open the layer for editing. You can edit the
attributes either by using the Attributes button on the Editor
toolbar, as you did for the historic park, or by editing directly
in the attribute table, as you’ll do here. To assign values in
the attribute table, you create a calculation expression. The
values are assigned to the selected parcels or to all the
parcels if none are selected.
7
7. Type “50” in the text box and click the dropdown arrow
and select Meters to select parcels using a buffer of
50 meters.
8. ClickApply.
The parcels within 50 meters of streets are selected.
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190 GETTING STARTED WITH ARCGIS
1. On the Editor toolbar, click the Editor dropdown arrow
and click Start Editing; click the Editor Toolbar button, if
necessary, to open the toolbar.
2. Click the Analysis folder as the folder to edit data from
and click OK. Click Start Editing to close the message
stating that you are starting to edit in a different
coordinate system.
3. Click the Target dropdown arrow and click parcel02sel
as the layer to edit.
4. Right-click parcel02sel in the table of contents and click
Open Attribute Table.
The selected parcels—those within 50 meters of a
road—are highlighted.
5. Scroll to the right in theAttributes window, right-click the
ROAD_DIST field—the mouse pointer changes to a
down arrow when it’s over the field name—and click
Calculate Values.
The Field Calculator dialog box appears. Since you
clicked the ROAD_DIST field, ArcMap starts the
calculation expression for you by displaying
ROAD_DIST =.
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PERFORMING THE ANALYSIS 191
6. Click in the expression box and type “50” to complete
the expression.
7. Click OK.
ArcMap assigns a value of 50 to the ROAD_DIST field
for the selected parcels—the ones within 50 meters of a
road. All other parcels have a value of 0 for
ROAD_DIST. You’ll use these values along with the
JUNC_DIST values to color code the highly suitable
parcels on your final map.
8. Click the Editor dropdown arrow on the Editor toolbar
and click Stop Editing. Click Yes when prompted to save
your edits.
When you save your edits, ArcMap clears the selected set
of features, so you’ll be able to start with the full set of
suitable parcels to find the ones near the wastewater
junction in the next step.
Keep the parcel02sel attribute table open since you’ll need
it in the next step, but you may want to move, resize, or
minimize it so you can see the map.
Measuring and assigning the wastewater junction
distance
The city would prefer that the plant site be within
1,000 meters of the point where the plant will connect to the
existing wastewater system. The council is willing to accept
parcels that extend beyond the 1,000-meter buffer as long
as most of the parcel is within the buffer. Parcels within
500 meters are even more desirable.
You need to find the parcels within 500 meters and
1,000 meters of the main wastewater junction and tag them
with the distance. For this task you’ll use a number of the
tools you used previously: buffer, selection, and attribute
editing. Rather than give you step-by-step instructions,
we’ve listed the major steps to give you a chance to work
through the task yourself. You can review the previous
sections if you need help with the specific steps.
6
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192 GETTING STARTED WITH ARCGIS
Add the wastewater junction coverage to the map (it’s
located in the utility folder under the City_share folder).
The junction coverage contains the main wastewater
junction point where the new plant will connect to the
existing system.
You will create a new model to buffer the wastewater
junction point. First, create a new toolbox named My Tools
if you haven’t done so already. Create a new model in the
My Tools toolbox.
Add the junction layer to the model. Add the Buffer tool to
the model and add a new connection from the junction layer
to the buffer. Set the Buffer parameters to buffer
500 meters. Confirm the path to your Analysis folder is set
and name the Output feature class junctionbuf500. Set
dissolve type to ALL.
Next, add another Buffer tool and add a new connection
from the junction layer to that tool. Set the Buffer2
parameters to buffer 1000 meters. Confirm the path to your
Analysis folder is set and name the Output feature class of
Buffer2 junctionbuf1000.Again, set the dissolve type to
ALL.
Click and drag the Union tool from ArcToolbox to the
model.Add a connection from junctionbuf500 and
junctionbuf1000 to the Union tool. Confirm the path to your
Analysis folder is set and name the Union Output feature
class junction02buf.
Run the model and add junction02buf to your map.
Name and save your model as Junction Buffer, then close.
The buffers draw on the map but obscure the junction and
the parcels. Change the symbology of the junction02buf
layer so the buffers are drawn with no shading (use “no
color” as the fill color).
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PERFORMING THE ANALYSIS 193
Now you can see which parcels are within 0 to 500 meters
and within 500 to 1,000 meters of the junction. Next, you’ll
select each set of parcels and tag them with the respective
distance.
Use the Select Features tool to select the 500- to 1,000meter
buffer by pointing at it and clicking. Then use Select
By Location to select the parcels in parcel02sel that have
their center in the selected features of junction02buf. This
will select all the parcels between 500 and 1,000 meters
from the junction. Close the Select By Location dialog box
when you’re done.
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194 GETTING STARTED WITH ARCGIS
Use the Editor toolbar to start editing parcel02sel; ensure
parcel02sel is the target layer. Open the attribute table for
parcel02sel—click the Restore button if you minimized it
before—and assign the value 1000 to the JUNC_DIST field
for the selected parcels. Save your edits, but don’t stop
editing yet. You’ll notice that some of the suitable parcels
are both within 50 meters of a road and 1,000 meters of the
junction, a few are more than 50 meters from a road but
within 1,000 meters of the junction, and quite a few are not
near either; both fields have values of 0.
Now switch the selected features for junction02buf so the
0- to 500-meter buffer is selected, or simply use the Select
Features tool to select the inner buffer. Then select by
location to select the parcels that have their center in the
selected features of junction02buf (i.e., the 0- to 500-meter
buffer). Now you’ll have only those parcels within
500 meters of the junction.
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PERFORMING THE ANALYSIS 195
Assign the value 500 to the JUNC_DIST field for the
selected parcels.
Stop editing and save your edits. Then save your map.
Now you’ve assigned the distance from the wastewater
junction to those parcels within 500 and 1,000 meters. On
your final map, you’ll color code the parcels based on their
distance to roads and the wastewater junction so the city
council and the public can see which are the highly suitable
parcels.
Another way of selecting the parcels near the junction
would have been to use Select By Location with a buffer
distance, but by creating the junction02buf layer you’ll be
able to display the rings on the map to make it easier for the
city council and public to visualize the distance from the
wastewater junction.
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196 GETTING STARTED WITH ARCGIS
Finding suitable parcels meeting the required total area
The final step in the analysis is to find suitable parcels that
are large enough on which to construct the wastewater
treatment plant. The minimum required area for
constructing the plant is 150,000 square meters. You’ll
check the parcel02sel attribute table to see which parcels
are at least this large.
Sorting the parcels by AREA
The parcel02sel attribute table should still be displayed.
1. Scroll to the left, if necessary, to see the AREA field.
2. Right-click AREA and click Sort Descending.
The largest parcels are listed at the top.
None of the suitable parcels is anywhere near
150,000 square meters in size. In fact, the largest one is
only a little more than 60,000 square meters (you may need
to scroll to the top of the table to see it). It looks like the
city is going to have to assemble the plant site from several
parcels or else relax its criteria to include more parcels as
possible sites. You’ll check to see if there are several
adjacent suitable parcels that total 150,000 meters.
Checking for adjacent parcels totaling
150,000 square meters
You’ll first identify several parcels to see how large they
are, then select a group of them to see if they total
150,000 square meters in area.
1. Right-click parcel02sel in the table of contents and click
Zoom To Layer, then uncheck junction02buf so it’s no
longer displayed. Move the attribute table to better see
the parcels, if necessary.
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PERFORMING THE ANALYSIS 197
2. Click the Identify Tool.
3. Click the Layers dropdown arrow in the Identify Results
dialog box and click parcel02sel.
That sets parcel02sel as the layer in which to identify
features. Leave the Identify Results dialog box open.
4. Click the parcel adjacent and just to the west of the
wastewater junction.
You can see that this parcel is just under 37,000 square
meters in area.
Identify
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198 GETTING STARTED WITH ARCGIS
5. Click the parcel to the left of the previous one.
This parcel is about 38,500 square meters. You can see that
most of the suitable parcels near the junction are about the
same size. It looks like four contiguous parcels together will
total about 150,000 square meters. Close the Identify
Results box.
6. Click the Select Features button.
7. Click and drag a box around the intersection of
four contiguous parcels.
The parcels are highlighted on the map and in the
attribute table.
8. Right-click AREA in the table and click Statistics.
The Selection Statistics dialog box appears.
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PERFORMING THE ANALYSIS 199
ArcMap calculates summary statistics about the selected
parcels and presents a graph of the distribution of values.
You’re not interested in the distribution of values in this
case, but the statistics are useful. You can see the number
of parcels selected (count), the size of the smallest and
largest parcels, the total area, and the mean size of the four
parcels.
The sum of the areas of these four parcels is slightly more
than 158,000 square meters. There is enough room for the
plant here. Further examination shows that there are a
number of combinations of adjacent suitable parcels that
will provide enough room for the plant. You can use the
Select Features tool to draw a box around different groups
of parcels, or select a parcel by clicking on it and clicking
additional parcels while pressing the Shift key to add them
to the selected set. Then recalculate the statistics to see the
total area.
9. Close the Selection Statistics dialog box and the attribute
table when you’re done selecting parcels.
10. Click Selection and click Clear Selected Features.
So it looks like the city will be able to piece together a site
for the plant. You decide to set up an interactive session at
the city council meeting using a big screen so you can query
different combinations of parcels on request from the
council members.
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200 GETTING STARTED WITH ARCGIS
Reviewing the analysis results
Anticipating one question the city council is likely to ask,
you decide to see if there are any parcels in the study area
at least 150,000 square meters in size and, if so, why they
didn’t make the final cut.
You’ll use select by attribute to find any parcels greater
than 150,000 square meters, then display them with the
analysis layers to see which criteria they do or don’t meet.
Finding any parcels at least 150,000 square meters
in size
1. Uncheck parcel02sel and streets and check parcel01mrg
so you can see all the parcels in the study area.
2. Right-click parcel01mrg in the table of contents and click
Zoom To Layer.
3. Click Selection and click Select By Attributes.
4. Click the Layer dropdown arrow and click parcel01mrg.
Use the default method (Create a new selection).
5. Double-click [AREA] in the Fields list, click the greater
than or equal to sign (>=), and type “150000” to create
the query expression.
The expression should look like this:
[AREA] >= 150000
6. ClickApply, then click Close to close the dialog box.
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PERFORMING THE ANALYSIS 201
There are three parcels of at least 150,000 square
meters.
First check to see if the parcels are vacant.
7. Right-click parcel01mrg in the table of contents and click
Open Attribute Table.
8. Click Selected at the bottom of the table window to
show just the selected parcels.
Two of the parcels have no land use code, but the other
has a code of 732, which is vacant (you may need to
scroll to the right to see the LANDUSE field).
9. Click the box next to the vacant parcel to highlight it. If
necessary, minimize or move the table so you can see
the highlighted parcel on the map.
So the two parcels in the upper left of the study area were
rejected because they weren’t classified as vacant land.
You’ll have to check with the City Assessor to find out the
actual land use for the parcels—it might be that they’re
vacant but were never assigned land use codes in the
database. In the meantime, though, you’ll check to see why
the third parcel was rejected.
10. Close the attribute table.
9
8
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202 GETTING STARTED WITH ARCGIS
Displaying the selected parcels with the criteria
layers
1. Check the respark_flood layer to display it.
You can see that the two parcels in the upper left are
mostly within this layer, which includes the flood zone and
buffers around parks and residential areas.
2. Check the flood_zone layer, then click and drag it above
respark_flood in the table of contents.
Now it’s clear that the two parcels are outside the
residential and park buffers but are within the flood zone.
So even if these parcels are vacant, they’d be rejected for
being inside the flood zone. The third parcel, though, is
outside the flood zone and the park and residential buffers.
3. Uncheck respark_flood and flood_zone and check
low_river.
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PERFORMING THE ANALYSIS 203
The city required that suitable parcels be completely or
mostly within this area. More than half of this parcel is
outside the area.
4. Check the lowland layer, then uncheck low_river.
The parcel is fully within the lowland layer, so it must be the
river buffer that it’s mostly outside of; that is, most of the
parcel is more than 1,000 meters from the river.
5. Uncheck lowland and check the river04buf layer.
Yes—that’s why it was rejected. Still, a portion of the
parcel is within the buffer, and the parcel is also adjacent to
the wastewater junction, a big plus. You decide to highlight
it on the final map to call it to the city’s attention as a
possible alternate site. Any additional construction costs
may be offset by the cheaper land costs involved in buying
a single parcel rather than four separate ones.
Creating a layer containing the alternate site
1. Click the Select Features tool.
2. Click inside the alternate site, but outside the river buffer,
so it is the only parcel selected.
2
Select Features
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204 GETTING STARTED WITH ARCGIS
3. Right-click parcel01mrg in the table of contents, point to
Selection, and click Create Layer From Selected
Features.
ArcMap adds the layer containing the single parcel to
the map.
4. Click the layer name (parcel01mrg selection) to select it,
then click again to highlight the name.
5. Type “alternate site” as the new layer name and press
Enter.
This is a temporary layer for this map—it is not stored as a
separate layer file. In the next chapter you’ll change its
symbology and add it to the final map.
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PERFORMING THE ANALYSIS 205
Cleaning up the table of contents
You won’t be using several of the analysis layers on your
final map, so you can remove them at this point.
1. Click flood_zone, then press the Ctrl key and click
respark_flood, low_river, lowland, river04buf, and
parks_polygon so they’re all selected.
2. Right-click one of the selected layers and click Remove.
At this point, your map should only include the following
layers:
• alternate site
• junction02buf
• junction point
• parcel02sel
• river03exp
• parcel01mrg
• streets
If any other layers are still on your map, go ahead and
remove them.
3. Click File and click Save to save your map.
The analysis phase of the project is finished, at least for
now. GIS makes it easy to modify your criteria and rerun
the analysis, if necessary.
There are many questions that GIS analysis can help you
answer as well as many different approaches. This analysis
showed one approach to solving a particular problem using
several of the most common GIS analysis tools: buffer,
overlay, and selection. You’ll combine these tools and others
in various ways when performing your own analyses.
In the next chapter you’ll make a map to present the results
of your analysis to the city council and the public.
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Ch07.pmd 2/16/2005, 1:19 PM206
IN THIS CHAPTER
207
Presenting the results
8
• Designing the map
• Setting up the map page
• Creating the overview map
• Creating the map of suitable
parcels
• Creating the map of highly
suitable parcels
• Creating the parcel report
• Adding the list of site criteria to
the map
• Adding the map elements
• Saving the map and printing it
• What’s next?
In this chapter you’ll create a poster-sized map to present the results of your
analysis. The poster will contain three maps. One map will show the
geographic relationship of the suitable parcels to the rest of the city. Another
map will show all of the suitable parcels. The third map will show the highly
suitable parcels symbolized according to their proximity to the main
wastewater junction and to roads. You will label these parcels with their
parcel identification numbers.
You’ll also create a report showing parcel identification numbers, area, and
distance from the junction for the highly suitable parcels.
The map will also include explanatory text, a North arrow, legends,
scalebars, and a title.
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208 GETTING STARTED WITH ARCGIS
Designing the map
You’ll want to give some thought to the map design before
you start laying out the map. The design should reflect how
the map will be used and who the audience for the map is.
In this case, your map will be displayed at a city council
meeting. The council members are probably familiar with
the issues involved in siting the wastewater treatment plant,
but the members of the public attending the meeting may
not be. Both groups will want to see the location of the
suitable parcels in relation to the rest of the city. They’ll
also want to see all the suitable parcels, as well as the most
likely candidates for the plant site, with additional
information about the highly suitable parcels.
You’ll first want to decide what elements will be on the map
and list them. Then decide how the elements will be
arranged on the page.
In this case, you’ll create three maps on one poster-size
page for display at the city council meeting.
1. An overview map of the city showing the location of the
study area and including the following layers:
• Streets (streets.lyr)
• The river (river03exp)
• The elevation grid (elevation_grid.lyr)
• The study area extent (graphic rectangle)
2. A map of the study area showing all suitable parcels and
including the following layers:
• Suitable parcels in one color (parcel02sel)
• Other parcels in a different color (parcel01mrg)
• The alternative site shaded using diagonal hatching
(alternate site)
• The wastewater junction (junction point)
• The 500- and 1,000-meter buffers around the junction
(junction02buf)
• The river (river03exp)
3. A map of the highly suitable parcels including the
following layers:
• Highly suitable parcels color coded by distance from
roads and from the wastewater junction and labeled
with their parcel numbers (parcel02sel)
• All other suitable parcels in a neutral color
(parcel02sel)
• The alternate site shaded using diagonal hatching and
labeled with its parcel number and area (alternate
site)
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PRESENTING THE RESULTS 209
You’ll also want to include other map elements and
explanatory text to make the map easier to understand and
more attractive.
The additional map elements are as follows:
• Report listing the highly suitable parcels
• Text block listing the site selection criteria
• Map title
• Scalebar for each data frame
• Legend for each data frame
• North arrow
• Citylogo
• Map reference information
• Graphic rectangles to complete the map composition
Once you’ve decided on what the maps should show and
what other elements to include, you’ll want to decide how
the elements will be arranged on the page. While it’s easy
in ArcMap to move and resize the individual maps and other
elements on the page, you may want to make a sketch on
paper to use as a guide. The sketch should show at least
the approximate position of the maps and map elements
and contain notes about the page size and map sizes. You
can reposition and resize the elements interactively as you
create the map.
Here’s a sketch for the map you’ll create:
Here are the major steps you’ll complete to create the map:
• Create the three data frames.
• Modify the data frames to show the required layers and
geographic extent.
• Create and add the parcel report.
• Add the text block listing the site criteria.
• Add the legends and scalebars for each data frame.
• Add the other map and graphic elements (North arrow,
title, logo, map reference information, graphic
rectangles).
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210 GETTING STARTED WITH ARCGIS
Setting up the map page
You’ll be creating a poster-sized map with three data
frames, one for each map. You’ll work in both Data view
and Layout view to create the map.
If necessary, start ArcMap and open the water project.mxd
map (located in the project folder). The map should
currently have the alternate site, junction point, and
parcel01mrg layers displayed.
Switching to Layout view
First you’ll switch from Data view to Layout view.
1. Click View and click Layout View.
The map switches to Layout view and displays the map
page filled by a data frame containing the currently
displayed layers. The Layout toolbar also appears.
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PRESENTING THE RESULTS 211
Layout view lets you view several data frames on a single
page and interactively work with the map elements. A data
frame is a way of organizing layers together on a map page.
Currently there is only one data frame on the page,
indicated by the rectangle.
The Layout toolbar contains tools for zooming and panning
on the page itself. The tools on the Tools toolbar let you
work with the data inside the data frame, just as you do in
Data view.
Changing the page size
You’ll set the page size to accommodate the final printed
map.
1. Right-click on the page, outside the data frame, and click
Page and Print Setup (if you right-click inside the data
frame, you open the Data Frame Properties dialog box).
The Page and Print Setup dialog box appears. The Use
Printer Paper Settings box is checked, indicating that
ArcMap will automatically detect the printer’s page size.
The city has another printer that is capable of printing
D size (22 x 34 inch) pages, so you don’t want the page
size to be the same as the default printer.
Zoom in
on map
page
Zoom in on
data in data
frame
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212 GETTING STARTED WITH ARCGIS
2. Uncheck Use Printer Paper Settings.
3. Click Size and click PostScript Custom Page Size.
4. Click the Standard Sizes dropdown arrow and click
Custom.
5. Type “34” in the Width text box and type “22” in the
Height text box. Make sure the units for each are set to
inches.
Now the virtual page for the map will be
22 x 34 inches—D size.
You want the map poster to be wider than it is high, so
change the page orientation.
6. Click Landscape in both the Paper and Page panels, then
click OK.
ArcMap adjusts the size and orientation of the page.
You’ll use the existing data frame to display the suitable
parcels. In the next steps you’ll resize the data frame and
make a copy of it to display the city overview map.
Resizing the data frame
First you will make this data frame smaller.
1. Click the Select Elements button.
Select
Elements
4
2
6
6
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PRESENTING THE RESULTS 213
2. Right-click near the middle of the data frame and click
Properties.
The frame is highlighted, selection handles appear at the
corners and sides of the frame, and the Data Frame
Properties dialog box appears.
3. Click the Size and Position tab.
You can move and resize elements on the page by clicking
and dragging the whole element or one of its selection
handles, or you can set the position and size by typing the
values in page units in the Data Frame Properties dialog
box. You’ll set the size and position of the first data frame
explicitly by typing the values.
You want the upper-left corner of the data frame to remain
where it is, but resize the data frame to be 12 by 9 inches.
4. Click the upper-left anchor point in the Position panel.
5. In the Size panel, type “12 in” in the Width box and
“9 in” in the Height box. Click OK.
The data frame is resized, and the layers are scaled
down to fit inside.
5
4
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214 GETTING STARTED WITH ARCGIS
Copying the data frame
Now you’ll make a copy of the data frame to contain the
city overview map.
1. Click Edit and click Copy.
2. Click Edit and click Paste.
The copy of the data frame is pasted onto the map on
top of the original data frame.
3. Click on the data frame and drag the copy to the right of
the original.
Both data frames display the same layers.
You’ll use the new data frame to show the position of the
project area with respect to the rest of the city and the
original one to show all of the suitable parcels. You’ll add a
third data frame to show the highly suitable parcels, but
first rename the other two.
Renaming the selected data frame
The table of contents is divided into sections by data frame.
Both data frames in the table of contents have the same
title—Layers (the default)—because you copied one to
create the other.
The data frame that you have just pasted onto the map is
still selected—you can see its selection handles in the
Layout view.
1. Scroll through the table of contents until you see the
Layers heading in bold type.
This is the data frame you just added. The bold type
identifies this data frame as the selected data frame.
2. Click the bold Layers heading in the table of contents to
select it.
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PRESENTING THE RESULTS 215
3. Click Layers again to highlight the name.
If you click twice rapidly—a double-click—on the name
of a data frame, you will open the Data Frame
Properties dialog box. You do not need to change any
properties of the data frame at the moment, so if you get
this dialog box, just click Cancel and try again.
You can now type a new name for the data frame.
4. Type “City Overview” and press Enter.
Renaming the original data frame
Now you’ll rename the other data frame.
1. Scroll through the ArcMap table of contents until you
see the Layers heading.
2. Click Layers to select the data frame, then click it again
to highlight the name.
3. Type “Study Area” and press Enter.
2
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216 GETTING STARTED WITH ARCGIS
Inserting a new data frame
Now add the third data frame, which will show the highly
suitable parcels. You’ll do this by inserting a new data
frame rather than copying an existing one.
1. Click Insert and click Data Frame.
The new data frame appears as the selected data frame
in the center of the map and is listed at the bottom of the
table of contents, named New Data Frame 2.
2. Click New Data Frame 2 in the table of contents to
select it, then click again to highlight the name.
3. Rename the data frame by typing “Best Parcels”, then
press Enter.
You want the new data frame to be the same size as the
others (12 by 9 inches) and positioned below the Suitable
Parcels data frame, so you’ll resize and move it.
4. Right-click inside the new data frame on the map and
click Properties.
5. Click the Size and Position tab.
6. Double-click in the Width text box and type “12 in”, then
double-click in the Height text box and type “9 in”. Click
OK.
The data frame is now the same size as the others.
6
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PRESENTING THE RESULTS 217
7. Click and drag the data frame so it is positioned below
the Study Area data frame. It’s OK if it’s not lined up
exactly—you’ll align the data frames later.
The data frame is currently empty. You’ll copy the layers
you need from the Study Area data frame later, after you’ve
changed their symbology.
8. Click File and click Save to save your map so far.
Through the rest of the chapter, you’ll want to periodically
save your map in case you need to stop or take a break and
come back to it. We’ll remind you at the end of each
section, but you may want to save more often.
At this point, you’ve added the three data frames to create
the basic structure of the map. Now you’ll modify each
data frame to display the necessary layers. In the next step
you’ll change the contents of the city Overview data frame
to show the location of the suitable parcels with respect to
the rest of Greenvalley.
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218 GETTING STARTED WITH ARCGIS
Creating the overview map
You want the City Overview data frame to show where the
suitable parcels are relative to the rest of Greenvalley.
Because most Greenvalley residents are familiar with the
major streets of Greenvalley, you can use the streets to
orient the map readers. You’ll also display the river and the
elevation grid so people can see that the study area
containing the parcels is near the river and in the low-lying
area. Later you’ll add a rectangle showing the location of
the study area.
To create the map, you’ll remove the unnecessary layers
from the City Overview data frame, change the extent of
the area displayed in the data frame, and change the way
the streets are displayed. Then you’ll change the way the
river is displayed and, finally, add the elevation grid layer
underneath.
Removing unnecessary layers from the data frame
It is often easier to work with the data in a given data
frame in Data view, particularly when the layout contains
several data frames.
1. Click inside the City Overview data frame on the map
page to select it.
2. Click View and click Data View.
On a map with multiple data frames, switching to Data
view shows you the data for the currently selected data
frame. In this case, the selected data frame is City
Overview.
3. Scroll to the City Overview data frame in the table of
contents, if necessary.
4. Click alternate site under the data frame heading in the
table of contents to select it.
1
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PRESENTING THE RESULTS 219
5. Press the Ctrl key and click the following layers to select
them as well:
• junction02buf
• junction point
• parcel02sel
• parcel01mrg
6. With the layers selected, point to one of the highlighted
layers, right-click, and click Remove.
The layers are removed from the map. You could have
left the layers in the data frame and just not displayed
them, but it’s easier to work with the data frame without
the layers in the table of contents.
You should now have only streets and river03exp in the
data frame. Neither are currently displayed. If any
additional layers remain, remove them as well.
7. Click the check boxes next to river03exp and streets to
display them.
8. Click the Full Extent button on the Tools toolbar.
This zooms to the full extent of the remaining layers.
Showing the major streets
The streets layer shows all of the streets of Greenvalley.
Displaying only the major streets will be sufficient for
showing the location of the suitable parcels and, in fact,
will make the map easier to read. You’ll modify the
properties of this layer to simplify the representation of the
streets.
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220 GETTING STARTED WITH ARCGIS
1. Double-click streets under the City Overview data frame
in the table of contents.
Double-clicking a layer is a quick way to get to its Layer
Properties dialog box.
2. Click the Definition Query tab.
3. Click the Query Builder button.
The Query Builder dialog box appears. It’s similar to the
other query dialog boxes you’ve already seen.
The Greenvalley streets in this database belong
to three classes. Classes 3 and 4 are major streets; class 5
streets are smaller streets. You will select the major streets.
4. Double-click [Type].
5. Click the less than or equal to button (<=).
6. Type “4”, review the query expression, then click OK.
The query expression is added to the Definition Query
tab of the Layer Properties dialog box. It should look
likethis:
[Type] <= 4
3
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PRESENTING THE RESULTS 221
7. Click OK on the Layer Properties dialog box.
Only the major streets are displayed—the smaller streets
are left off the map. Using Definition Query is a quick
way of showing only certain features in a layer without
selecting them and creating a separate layer.
Now you can zoom to the area covered by the major
streets.
8. Right-click streets in the table of contents and click
Zoom To Layer.
Changing the street symbol
Because you have not yet specified a symbol for the
streets, they are drawn in a randomly selected color. You
want the streets to be drawn with a simple black line.
1. In the table of contents, click the line symbol below the
streets layer (you may need to scroll through the table of
contents to locate it).
Note that streets are also in the Study Area data
frame—make sure you’re working with the layers under
the City Overview data frame.
1
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222 GETTING STARTED WITH ARCGIS
2. Click the Major Road symbol and click OK.
The major streets of Greenvalley are now drawn on the
map with a black line.
Displaying the river and elevation layers
You also want to display the river and elevation grid so the
city council and public can see that the study area was
chosen based on its proximity to the river and its location in
a low-lying area.
1. Click the line symbol beneath the river03exp layer name.
2. Click the River symbol and click OK.
The river is now drawn with a blue line.
3. Click the Add Data button, navigate to the City_layers
folder, and click elevation_grid.lyr. ClickAdd.
If you get a warning message about the coordinate system
for the layer, click OK.
The elevation grid is added to the data frame and is
displayed using the colors you specified when you created
the layer.
2
2
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PRESENTING THE RESULTS 223
The City Overview should now display the following layers,
listed in this order in the table of contents:
• river03exp
• streets
• elevation
4. Click View and click Layout View.
The City Overview data frame on the map now shows
the major streets, the river, and the elevation grid.
ArcMap attempts to center the layers in the data frame.
Since the river is along the top edge, it is only partially
visible.
5. Click the Pan tool on the Tools toolbar.
6. Click in the data frame and drag the layers down so the
river is visible near the top of the data frame.
The data frame is finished for now.
Later in the chapter you’ll add a rectangle to this frame to
show the location of the study area.
7. Click File and click Save to save your map.
In the next step, you’ll make the necessary changes to the
Study Area data frame to show the suitable parcels.
Pan
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224 GETTING STARTED WITH ARCGIS
Creating the map of suitable parcels
This map will show suitable parcels shaded in one color and
all other parcels in another color. It will also show the
location of the wastewater junction, along with the 500and
1,000-meter buffers around the junction. The map will
also include the alternate site, shaded using a diagonal
hatched pattern, and will display the river to help orient
map readers to the location of the parcels.
Setting the display environment
1. Click the Select Elements tool on the Tools toolbar.
2. Click the Study Area data frame on the page—the one in
the upper left.
The data frame is selected and highlighted on the map,
and the data frame name is shown in bold type in the
table of contents. To make it easier to see the data
you’re working with, switch to Data view.
3. Click View and click Data View.
You’ll be displaying all the listed layers in this data frame,
except streets, so remove the streets layer.
4. Right-click streets in the table of contents and click
Remove.
The data frame should now contain the following layers,
listed in this order in the table of contents:
• alternate site
• junction02buf
• junction point
• parcel02sel
• river03exp
• parcel01mrg
If the data frame contains any other layers, you can remove
them.
Currently, alternate site, junction point, and parcel01mrg
should be displayed.
Changing the symbol for the parcels
You’ll use the parcel01mrg layer as a background layer.
This layer contains all the parcels in the study area. The
foreground data in this data frame will be the layer
containing only the suitable parcels (parcel02sel). It will
display on top of the parcel01mrg layer.
1. Right-click parcel01mrg in the table of contents and click
Zoom To Layer.
The parcels fill the data frame.
2
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PRESENTING THE RESULTS 225
You want to emphasize the suitable parcels when you draw
them on top, so change the color for the parcels in this
layer to a light shade.
2. Right-click the parcel01mrg layer in the table of
contents and click Properties.
3. Click the Symbology tab.
4. Click the Symbol button.
5. Click the Fill Color dropdown arrow and click Blue Gray
Dust.
6. Click OK.
7. Click the Display tab on the Properties dialog box.
8. In the Transparent text box, type “70”.
8
4
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226 GETTING STARTED WITH ARCGIS
That will set the parcel fill color to be a lighter shade of
the Blue Gray Dust color.
9. Click OK.
The parcels are now drawn in a light blue-gray.
Displaying the suitable parcels
1. Check the box next to the parcel02sel layer to display it.
2. Click the symbol box beneath parcel02sel.
3. Click the Fill Color dropdown arrow and click Blue Gray
Dust.
4. Click OK on the Symbol Selector dialog box.
Now the suitable parcels are drawn using a medium
blue-gray, a darker shade of the color the rest of the
parcels are drawn with.
2
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PRESENTING THE RESULTS 227
Changing the symbol for the alternate site
Right now the alternate site is drawn using the default color
ArcMap selected when you created the layer. You’ll draw it
using gray diagonal hatching so it is visible but doesn’t
detract from the suitable parcels.
1. Click the symbol box beneath the alternate site layer to
display the Symbol Selector dialog box.
2. Scroll to the bottom and click 10% Simple hatch.
3. Click the Fill Color dropdown arrow and click Gray 40%.
4. Click OK.
The picture redraws with the gray diagonal hatching.2
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228 GETTING STARTED WITH ARCGIS
Displaying the river and the wastewater junction
You’ll also want to display the river and wastewater
junction to show where the suitable parcels are in relation
to these features. You know how to change the symbology
for a layer at this point, so we’ll just give you the major
steps. If you need help, review the specific steps in the
previous sections.
Display the river03exp layer and draw it using the same
symbol you used for the river in the City Overview data
frame.
The wastewater junction should already be displayed. Click
the point symbol underneath the layer to display the
Symbol Selector dialog box. Click a symbol of your
choosing. You can use the Color dropdown arrow to change
the color if you like. Use the arrows in the Size text box to
set the size to 14 (points).
Displaying and labeling the junction buffers
Finally for this map, you’ll want to display and label the
500- and 1,000-meter buffers around the wastewater
junction.
1. Click the check box next to the junction02buf layer to
display it.
Now you’ll label the two buffers by adding text to the data
frame. You can also label features using a value stored in
the attribute table. You’ll do that later, on the map of highly
suitable parcels.
2. Click the New Text button on the Draw toolbar.
The cursor changes to a crosshair and an A.
New Text
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PRESENTING THE RESULTS 229
3. Move the cursor next to the upper-right edge of the
inner buffer circle and click.
A text box appears.
4. Type “500 meters” and press Enter.
The text box is still active and highlighted with a box.
5. Click the Bold button on the Draw toolbar to make the
text appear in bold type.
If you make a mistake, simply click the text to select it,
press the Delete key on the keyboard, and start over.
6. With the text still selected, click and drag it to reposition
it away from the outer buffer circle, if necessary.
7. Add the second label, 1000 meters, in the same manner.
8. Click View and click Layout to switch back to layout
view and display your map at this point.
9. Click File and click Save to save your map.
You’ve completed two of the maps. In the next section
you’ll create the map of the highly suitable parcels.
Bold
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230 GETTING STARTED WITH ARCGIS
Creating the map of highly suitable parcels
The third map will focus on the highly suitable parcels,
color coding them by their distance from roads and the
wastewater junction. You’ll also label each parcel with its
assessor’s parcel number (APN) so people can associate
the parcels on the map with the parcel report you’ll create.
Finally, you’ll label the alternate site with its area.
You’ve already changed the symbols in the Study Area data
frame for several of the layers, so you’ll copy the layers
you need from that data frame into the Best Parcels data
frame. Then all you’ll need to do is change the color coding
for the highly suitable parcels and label them.
Copying layers from the Study Area data frame
Now you can copy the layers you need into the empty data
frame. Since the changes you need to make to the layers are
minimal, you can continue to work in Layout view. The map
will be updated as you make the changes.
The order in which you add the layers to the data frame
determines the order in which they are drawn, with the
most recently added drawn on top. To maintain the correct
order, copy them in the reverse order to the order that they
appear in the table of contents.
1. Right-click the parcel01mrg layer under the Study Area
data frame in the table of contents and click Copy.
2. Right-click the Best Parcels data frame in the table of
contents and click Paste Layer.
The parcel01mrg layer is added to the Best Parcels data
frame and appears on the map.
Now copy the rest of the layers you need, in this order:
• parcel02sel
• junction point
• alternate site
The Best Parcels data frame should now display these
layers listed in the following order in the table of contents:
• alternate site
• junction point
• parcel02sel
• parcel01mrg
Creating the layer of the highly suitable parcels
To make it easier to display and label the highly suitable
parcels, you’ll select them and create a new layer in the
data frame. You’ll do this by creating a selection
expression. In Layout view, queries are performed on the
selected data frame. You have been adding layers to the
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PRESENTING THE RESULTS 231
Best Parcels data frame, but it is not the selected data
frame—Study Area is selected. Before you can query the
parcels layer, you have to select the Best Parcels data
frame.
1. Click the Best Parcels data frame on the virtual page to
select it.
Now you can select the highly suitable parcels—those
within 50 meters of a road and/or 1,000 meters of the
wastewater junction. These parcels have values greater
than 0 for either or both the ROAD_DIST and
JUNC_DIST fields.
2. Click Selection and click Select By Attributes.
The Select By Attributes dialog box appears.
3. Click the Layer dropdown arrow and click parcel02sel.
4. Double-click ROAD_DIST in the Fields list.
5. Click the greater than button (>).
6. Type “0”.
7. Click Or.
8. Double-click JUNC_DIST.
9. Click the greater than button (>).
10. Type “0”.
1
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232 GETTING STARTED WITH ARCGIS
The selection expression should look like this:
“ROAD_DIST” > 0 OR “JUNC_DIST” > 0
11. ClickApply, then click Close.
Now the highly suitable parcels are selected, and you
can create a separate layer containing them.
12. Right-click parcel02sel in the table of contents—under
the Best Parcels data frame—point to Selection, and
click Create Layer From Selected Features.
ArcMap creates a new layer in the Best Parcels data
frame that contains the selected features. The default
name is parcel02sel selection. You will rename it to
“highly suitable”.
13. Click parcel02sel selection in the table of contents to
select it, then click again to highlight the name.
14. Type “highly suitable” and press Enter.
The layer is renamed in the table of contents. Now you
will change the way it is symbolized and add the parcel
identification numbers as labels on the map.
Color coding the highly suitable parcels
You’ll color code the highly suitable parcels based on both
their distance from roads and from the wastewater junction,
using the ROAD_DIST and JUNC_DIST fields. There are
five possible pairs of values:
• Less than 500 meters from the junction and less than 50
meters from a road (junc_dist = 500 and road_dist = 50)
• Less than 500 meters from the junction but more than 50
meters from a road (junc_dist = 500 and road_dist = 0)
• 500 to 1,000 meters from the junction and less than 50
meters from a road (junc_dist = 1000 and road_dist =
50)
• 500 to 1,000 meters from the junction but more than 50
meters from a road (junc_dist = 1000 and road_dist = 0)
• More than 1,000 meters from the junction but less than
50 meters from a road (junc_dist = 0 and road_dist = 50)
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PRESENTING THE RESULTS 233
These distance values may play a part in the city council’s
decision of which parcels to buy for the plant site. The
parcels closer to the junction and closer to a road are the
most suitable, although other factors may come into play in
the decision, such as engineering issues (the slope and soils
on-site) and economic issues (the ownership and assessed
value of each parcel).
You’ll symbolize the highly suitable layer so that both
distance values are communicated.
1. Double-click the highly suitable layer under the Best
Parcels data frame in the table of contents.
2. Click the Symbology tab.
Currently, all the parcels are drawn with a single default
symbol.
3. Click Categories in the Show box and click Unique
values, many fields.
The Unique values, many fields option lets you color code
features based on combinations of values from up to
three fields. You need only two: JUNC_DIST and
ROAD_DIST.
4. Click the top dropdown arrow in the Value Fields
section and click JUNC_DIST.
5. Click the second dropdown arrow in the Value Fields
section and click ROAD_DIST.
6. Click Add All Values.
Only four pairs of values are listed. Apparently there are no
parcels in the fifth category (more than 1,000 meters from
the junction, but less than 50 meters from a road).
The pairs appear in this order:
• 500, 50
• 500, 0
• 1000, 50
• 1000, 0
The four pairs of values will be shown on the map with
unique symbols. You’ll draw the parcels within 500 meters
of the junction in two shades of green—parcels near a road
in a dark shade and parcels far from a road in a lighter
shade—and the parcels between 500 and 1,000 meters
from the junction in two shades of yellow. The remaining
parcels—those meeting all the city’s criteria but more than
50 meters from a road and more than 1,000 meters from the
junction—will be shaded using the same blue-gray you used
in the Study Area data frame.
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6
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Changing the symbol colors
ArcMap uses default colors for the value combinations. You
want to use two shades of green for the parcels within
500 meters of the junction and two shades of yellow for
parcels between 500 and 1,000 meters of the junction.
1. Double-click the symbol box next to 500, 50.
The Symbol Selector dialog box appears.
2. Click the Fill Color dropdown arrow and click Tarragon
Green.
3. Click OK.
4. Now select the colors for the other values in the same
manner. Use the following colors:
500, 0 Lemongrass
1000, 50 CitroenYellow
1000, 0 YuccaYellow
There are no other values in this case, so you can turn off
the symbol for other values.
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PRESENTING THE RESULTS 235
5. Click the check box next to <all other values> to
uncheck it.
You also want to change the legend labels, so keep the
dialog box open.
Changing the heading and value labels
Now you’ll change the labels that appear in the table of
contents to make them easier to understand. These labels
will also appear in the map legend when you create it.
1. Click the label field for the Heading and type “Distance
to: Junction, Road”. Rather than pressing Enter, which
will close the dialog box, just click in the next label field
to change the label.
2. Click the label field for 500, 50 and type
“<500m; <50m”.
3. Change the labels for the remaining three symbols.
For 500, 0 type “<500m; >50m”.
For 1000, 50 type “500–1000m; <50m”.
For 1000, 0 type “500–1000m; >50m”.
4. Click OK.
Now the highly suitable parcels have unique symbols based
on distance from roads and the wastewater junction. The
parcels shaded green are within 500 meters of the junction,
and the parcels shaded yellow are between 500 and
1,000 meters from the junction. The dark-shaded parcels—
both green and yellow—are within 50 meters of a road,
while the lighter shaded parcels are more than 50 meters
from a road.
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236 GETTING STARTED WITH ARCGIS
Labeling the highly suitable parcels
Next, you’ll label the highly suitable parcels with theirAPN
so they can be identified in the parcel report. First, zoom to
the highly suitable parcels to emphasize them on the map.
1. Click the Zoom In tool on the Tools toolbar and click and
drag a rectangle around the highly suitable parcels and
the alternate site.
Since you’re zooming in on the data—not the map
page—make sure you’re not using the Zoom In tool on
the Layout toolbar.
Before you add the labels, you will make sure that the
correct field is used for labeling.
2. Double-click highly suitable.
3. Click the Labels tab of the Layer Properties dialog box.
4. Click the dropdown arrow to select the label field and
click APN.
5. Check Label Features in this layer in the upper-left
corner of the dialog box and click OK.
Each highly suitable parcel is now labeled with its APN.
It’s hard to see how the labels will look since the map is
currently scaled down to fit the screen. You can display the
map at the actual size to see how it will look when printed.
6. Click the Zoom to 100% button on the Layout toolbar.
5
4
Zoom to 100%
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PRESENTING THE RESULTS 237
The map is now displayed in the ArcMap window at the
printed size, but you’re looking at the center of the map.
7. Click the Pan tool on the Layout toolbar and drag the
map to the upper right until you can see the highly
suitable parcels with their labels.
The Pan and Zoom tools on the Layout toolbar let you
move around the map page, whereas Pan and Zoom on
the Tools toolbar let you change the geographic extent of
the data displayed in the currently selected data frame.
The labels look pretty good, but they could be a little larger.
8. Double-click the highly suitable layer in the table of
contents to display the Layer Properties dialog box and
click the Labels tab.
9. Click Symbol.
Pan
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238 GETTING STARTED WITH ARCGIS
The Symbol Selector dialog box appears. The labels are
currently displayed using 8 point type.
10. Click the Size dropdown arrow and click 12 to make the
labels 12 point. Click OK.
11. Click OK on the Layer Properties dialog box.
The labels are now larger and easier to read.
12. Click the Zoom Whole Page button on the Layout
toolbar to see the entire map again.
Creating the label for the alternate site
The alternate site won’t be in the parcel report since it
doesn’t meet all the city’s current criteria for a site for the
wastewater treatment plant. However, you want to display
its area. You’ll label the parcel with its AREA field using the
Layer Properties dialog box to set the properties before
displaying the label.
1. Double-click alternate site in the table of contents to
display the Layer Properties dialog box.
2. Click the Labels tab.
3. Click Expression.
The Expression Properties dialog box appears. You can
create a Visual Basic or Java™ script to customize the
way labels are displayed. You’ll create a simple VB
script to display the area value with a suffix of
“sq meters”. The area value is stored in the database
using several decimal places, which you don’t need toZoom Whole
Page
Q
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PRESENTING THE RESULTS 239
display, so you’ll round the value to no decimal places.
You will need to create an expression that looks like this:
Round([AREA], 0) & “ ” & “sq meters”
4. Click in the Expression box.
5. Type the expression in full or type all the characters
except the field name, which you can drag from the
Label Fields box.
The VB Round command has two arguments, enclosed
in parentheses—the name of the field, AREA in this
case, and the number of decimal places to round to, 0 in
this case. You enclose in double quotes any text you
want to display as part of the label, in this case “sq
meters”. The double quotes with two spaces inside will
ensure there is space between the area value and the
suffix when the label is displayed. You use an ampersand
(&) to connect the elements of the script.
6. Click the Verify button to make sure you entered the
expression correctly.
The Sample label box appears and tells you the
expression is valid. It also shows you a sample of how
the label will look. If you get an error message when
you click Verify, just check that you entered the
expression correctly, make any changes, and click Verify
again.
7. Click OK to close the Sample label dialog box and click
OK to close the Expression Properties dialog box.
Now you’ve specified what will be in the label. Next you’ll
want to change the way the label is displayed.
Changing the label properties and displaying the
label
1. Click Symbol on the Labels tab.
The Symbol Selector dialog box appears.
2. Click the Size dropdown arrow and click 12 to make the
label 12 point text.
Now the label will be large enough, but it will be drawn on
top of the diagonal hatching and might still be difficult to
read. You’ll add a mask around the text so it appears on a
solid background.
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240 GETTING STARTED WITH ARCGIS
3. Click Properties.
The Editor dialog box appears to let you edit the text
properties. You can see that the size is shown as 12, as
you just specified.
4. Click the Mask tab.
5. Click Halo in the Style panel.
The Preview panel shows you how the text will look. You
want the mask to be wider to block out the hatching in the
alternate site parcel.
6. Click the up arrow in the Size text box to increase the
mask width to 4 points.
You also want the mask to be light gray so it’s easy to read
the text.
7. Click Symbol to display the mask Symbol Selector dialog
box.
8. Click the Fill Color dropdown arrow and click Gray 10%.
9. Click OK to close the mask Symbol Selector.
The Preview panel shows that the mask is light gray.
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4
5
6
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PRESENTING THE RESULTS 241
10. Click OK to close the Editor dialog box and click OK
again to close the text Symbol Selector dialog box.
11. Check Label Features in this layer in the upper-left
corner of the dialog box and click OK.
The alternate site is labeled with its area.
12. Click the Zoom In tool on the Layout toolbar and click
and drag a rectangle around the alternate site.
You can see the label with its mask.
13. When you’re done reviewing the label, click the Zoom
Whole Page button on the Layout toolbar to view the
entire map again.
14. Click File and click Save to save your map at this point.
The third map is complete, and the geographic information
you need to present is now displayed in each data frame.
Next, you’ll create a report for the highly suitable parcels,
add it to the map, and finish laying out the map by adding
the rest of the map elements.
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242 GETTING STARTED WITH ARCGIS
Creating the parcel report
You’ll create a tabular report of the highly suitable parcels
to provide additional information about each. The report
will list the assessor’s parcel number, area, and distance
from the junction for each parcel. You’ll group the parcels
by distance from the junction and sort them by size.
First you’ll design the report—specifying what should be
included—then you’ll generate it and add it to the map.
Designing the report
You’ll specify the fields you want in the report, then you’ll
specify how to group and sort the parcels.
1. Click Tools, point to Reports, and click Create Report.
The Report Properties dialog box appears, and the Fields
tab is selected. The other tabs are unavailable since you
haven’t yet specified any fields to include in the report.
2. Click the dropdown arrow in the Layer/Table text box
and click highly suitable as the layer to create the report
from.
3. Double-click JUNC_DIST to move it from the Available
Fields to the Report Fields column.
4. Double-click APN and AREA to add them to the Report
Fields column as well.
Now the other tabs are available.
5. Click the Grouping tab.
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PRESENTING THE RESULTS 243
6. Double-click JUNC_DIST to specify this as the
grouping field.
Parcels less than 500 meters from the wastewater junction
will be in one section of the report, and the parcels between
500 and 1,000 meters from the junction will be in another.
7. Click the Sorting tab.
Here you specify which fields to use to sort the records and
how to sort them.
8. Click in the Sort column for AREA and click
Descending on the dropdown list that appears.
The largest parcel will be listed at the top for each group.
You’ll need to change the width for the APN column to
make it wide enough to display the full assessor’s parcel
number.
9. Click the Display tab, click Fields, and click APN.
10. Double-click in the box next to Width and type 1. Press
Enter.
Generating the report
Now have ArcMap generate the report using the settings
you have specified.
1. Click Generate Report.
The Report Viewer appears. The viewer lets you
preview the report.
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244 GETTING STARTED WITH ARCGIS
The report looks good, so add it to the map.
2. ClickAdd.
The Add to Map dialog box appears.
The report is only one page long, so you will accept the
default settings.
3. Click OK.
The report appears on the map.
4. Click the X button to close the Report Viewer and click
the Close button to close the Report Properties dialog
box.
The Report tool asks if you want to save this report.
5. Click No.
6. Click the Select Elements tool, if necessary.
7. Click and drag the report into position beside the Best
Parcels data frame.
8. Click File and click Save to save your map.
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PRESENTING THE RESULTS 245
Adding the list of site criteria to the map
So that the public as well as the city council will be aware
of the criteria used for finding a site for the plant, you’ll
add a text file listing the criteria. The city council staff
e-mailed you a text file containing a copy of the criteria.
The file is stored in the project folder.
1. Click Insert and click Object.
The Insert Object dialog box appears.
2. Click Create from File, then click the Browse button.
3. Navigate to the project folder, click Site Criteria.rtf, and
click Open.
4. Click OK.
The text file is added to the map.
5. Click and drag the text to the right of the parcel report.
If you want, you can make the text smaller by using the
green selection handles to resize the text block. Click the
lower-left selection handle and drag it toward the upperright
selection handle. Holding the Ctrl key while you
drag the handle will reduce the text proportionally. It’s
okay if the selection box extends beyond the map page
since it won’t be visible once the text block is no longer
selected.
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246 GETTING STARTED WITH ARCGIS
Adding the map elements
At this point you’ve added to the map the content you need
to present to the city council. Now you’ll add the map
elements to make the map easier to read and more visually
attractive.
Here are the elements you will add:
• An extent rectangle to show the location of the study
area on the City Overview data frame
• Map legends
• Scalebars
• A North arrow
• The map title
• The city logo
• Map reference information
• Graphic rectangles to create a title bar and to enclose
the map
Adding an extent rectangle to the City Overview
map
You will add an extent rectangle to the City Overview data
frame that will show the location of the suitable parcels
relative to the rest of the city. Extent rectangles show the
size, shape, and position of one data frame in another data
frame.
First you’ll need to select the City Overview data frame.
1. Click the Select Elements button, if necessary.
2. Click the City Overview data frame to select it.
3. Right-click the data frame and click Properties.
The Data Frame Properties dialog box appears.
4. Click the Extent Rectangles tab.
You will show the position of the Study Area data frame.
5. Click Study Area in the Other data frames list.
6. Click the top arrow button to move Study Area to the
right list box.
ArcMap lets you choose a variety of symbols for the extent
rectangle, but the default line will work just fine. If you
want to change the symbol, click the Frame button to
display the Frame Properties dialog box.
7. Click OK on the Data Frame Properties dialog box.
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PRESENTING THE RESULTS 247
The extent rectangle appears in the City Overview data
frame, showing the position and extent of the Study
Area data frame, but it’s clipped by the edge of the data
frame.
8. Click the Pan tool on the Tools toolbar and drag the
layers down and to the right until the entire extent
rectangle is visible.
The city council and public will now be able to see the
location of the suitable parcels relative to the major
streets of Greenvalley.
Adding the map legend for the City Overview map
You’ll want to add legends and scalebars for all three data
frames. You’ll select each data frame and create the legend
and scalebar for each in turn. ArcMap automatically
creates a legend based on the table of contents for each
data frame. Once you’ve created the legend you can move,
resize, and edit it.
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248 GETTING STARTED WITH ARCGIS
The City Overview data frame should still be selected.
1. Click Insert and click Legend.
If the Legend Wizard dialog box appears, the ArcMap
option to ‘Use wizards when available’ is turned on; if
needed, this option is under Options on the Tools menu
on the General tab. You can proceed with the
following steps using the wizard. If the Legend Wizard
doesn’t appear and the legend is added immediately to
the map, skip to step 5 below.
The wizard automatically lists all the layers in the data
frame for inclusion in the legend. You want all the layers
for this map.
2. Click Next.
You don’t need a title for the legend, so double-click
Legend and press the Backspace key to delete the text.
3. Click Preview.
The legend is displayed in the center of the map (you
may have to move the wizard dialog box to see it).
You’ll use the default settings for the rest of the legend
properties, so you can exit the wizard at this point.
4. Click Finish.
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PRESENTING THE RESULTS 249
5. If necessary, click the selection handle in the upper-right
corner of the legend box and drag it to the lower left
until the legend will be small enough to fit on the page,
to the right of the City Overview data frame.
6. Click and drag the legend to the right of the City
Overview data frame.
7. Click the Zoom In tool on the Layout toolbar and click
and drag a rectangle around the legend so you can see it
better.
You’ll notice that the text for the river symbol reads
river03exp, and the label for the elevation layer is “Value”.
ArcMap takes the legend text directly from the table of
contents. You want to use more explanatory text in the
legend. This is easy to change.
8. Click river03exp under the City Overview data frame on
the table of contents to select it. Click again to highlight
the name.
9. Type “river” and press Enter.
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250 GETTING STARTED WITH ARCGIS
The legend is updated with the new text.
Now change the text for the elevation layer.
10. Click Value under the elevation layer to select it, then
click again to highlight the name. Type “elevation” and
press Enter.
11. Click the Zoom Whole Page button on the Layout
toolbar to see the entire map again.
Adding a scalebar for the City Overview map
Each of the three data frames on the map is drawn at a
different scale, so you’ll need to add a scalebar for each.
You’ll add a scalebar for the City Overview data frame
while it’s still selected.
1. Click Insert and click Scale Bar.
The Scale Bar Selector dialog box appears.
2. Click a scalebar that appeals to you and click OK.
The scalebar is added to the map.
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PRESENTING THE RESULTS 251
3. Click the scalebar and drag it below the City Overview
data frame.
ArcMap knows the scale of each data frame and creates
the scalebar accordingly.
Adding the other legends and scalebars
Now you know how to add legends and scalebars to your
map. We’ll give you the major steps for the other two data
frames, and you can work through the tasks yourself. You
can review the previous sections if you need help with the
specific steps.
Select the Study Area data frame by clicking it. Insert a
legend. You don’t need to include the junction buffers or
the parcel01mrg layers in the legend, so remove them from
the Legend Items list in the wizard. Click each and click the
< arrow at the bottom to move them off the list. You want
the layers to appear in the following order in the legend:
parcel02sel, alternate site, junction point, and river03exp.
Click parcel02sel in the list and click the up arrow twice to
move it to the top. The layers should now be in the right
order. The legend doesn’t need a title, so remove it on the
next screen in the wizard. Then preview the legend and
click Finish to add it to the map. If you’re not using the
wizard, after the legend is added to the map right-click it
and click Properties. Then click the Items tab to change the
layers that are displayed and click the Legend tab to
remove the title.
Click and drag the legend to the right of the Study Area
data frame. Make the legend small enough to fit between
the two data frames by clicking and dragging the upperright
selection handle, if necessary.
Change junction point to junction, river03exp to river, and
parcel02sel to suitable parcels.
Insert a scalebar for the Study Area data frame. Use the
same style you used for the City Overview and drag it
under the Study Area data frame; you may want to zoom
and pan on the page to position the scalebar.
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252 GETTING STARTED WITH ARCGIS
If you zoom in on the two scalebars you’ve added so far,
you can see that the City Overview map is about half the
scale of the Study Area map.
Select the Best Parcels data frame and insert a legend. You
only need to include the highly suitable parcels, the alternate
site, and the wastewater junction, in that order. This time
include a title for the legend: Highly Suitable Parcels.Add
the legend to the map; reduce its size, if necessary, by
clicking and dragging one of the corner selection handles;
and drag it to the right of the Best Parcels data frame,
below the report.
Finally, add a scalebar for the Best Parcels data frame and
position it below the frame.
Save your map at this point.
Now you are ready to add a few final map elements to
finish the map. You’ll include a North arrow, a map title,
the city logo, and map reference information. You’ll also
add two graphic rectangles to tie the composition together.
Adding a North arrow
You’ll place a North arrow in the upper-left corner to show
the orientation of the whole map.
1. Click Insert and click North Arrow.
The North Arrow Selector dialog box appears.
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PRESENTING THE RESULTS 253
2. Click any of the North arrows, then click OK.
The North arrow appears on the map.
3. Click the North arrow and drag it to the upper-left
corner of the map so it is a little lower than the top of
the Study Area data frame.
Adding a map title
Next you’ll add a descriptive title to the map, placed
vertically along the left side of the page.
1. Click Insert and click Title.
The text water project appears on the map. ArcMap
uses the name of the map file as the default title.
2. Type “Potential Wastewater Plant Sites”.
3. On the Draw toolbar, type “72” in the font size text box
and press Enter.
The map title is redrawn in 72 point type.
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254 GETTING STARTED WITH ARCGIS
4. Right-click the title, point to Rotate or Flip, and click
Rotate Left.
The title is rotated. Now you can place it along the left
edge of the map.
5. Click on the title and drag it to the left edge of the map
below the North arrow.
Adding the city logo
The map needs to have the city logo on it. You’ve got a
bitmap version of the logo that you’ve used for previous
projects stored in the project folder.
1. Click Insert and click Picture.
2. Navigate to the project folder.
3. Click city_logo.bmp and click Open.
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PRESENTING THE RESULTS 255
The logo is added to the map. You’ll need to make it
smaller and move it.
4. Right-click the logo and click Properties.
5. Click the Size and Position tab.
6. Uncheck the As Percentage box and check the Preserve
Aspect Ratio box.
7. Click in the Width box and type “2.5in” to make the logo
2.5 inches wide. Click OK.
8. Click and drag the logo to the lower-right corner of the
map.
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Adding the map reference information
You’ll want to add information about the map itself for
reference. At a minimum, this should include the map
projection information and the date. You can also include
your name, as the author of the map, if you’d like.
1. Click the New Text tool on the Draw toolbar.
2. Click beneath the logo.
In the text box, you’ll type the map projection information
on the first line and the date on the second line.
3. Type “UTM Zone 11N, NAD 1983”.
4. Press the Ctrl key and press Enter to add a line break; if
you press Enter without the Ctrl key, the text will be
added to the map immediately.
5. Type today’s date on the second line.
6. If you’d like, press Ctrl + Enter again and type your
name.
7. Press Enter to add the text to the map.
The text box is still selected. You want to use 12 point type.
8. Click in the text size box on the Draw toolbar, type “12”,
and press Enter.
In an actual GIS project you might also include the sources
of the data used on the map and the dates the data was
collected, other contributors to the map, copyright
information, and so on.
9. If necessary, click and drag the text to reposition it so it
lines up with the left edge of the logo.
10. Click File and click Save to save your map.
Aligning the map elements
So far, you’ve added all the elements to the map that you
needed—the extent rectangle, legends, scalebars, North
arrow, title, and logo—and arranged them on the page.
Before adding the graphic rectangles to complete the map,
you’ll want to align the data frames and other map
elements.
1. Click the Study Area data frame to select it.
2. Press and hold the Shift key and click the Study Area
legend, the City Overview data frame, and the City
Overview legend so that all four elements are selected.
New
Text
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PRESENTING THE RESULTS 257
3. Click the Drawing dropdown arrow on the Draw toolbar,
point toAlign, and clickAlign Bottom.
The bottom edges of the four elements now line up. You
can align other combinations of map elements the same
way.
Select the scalebars below the Study Area and City
Overview data frames and use Align Vertical Center.
Select the Best Parcels data frame and its legend and use
Align Bottom.
Select the Study Area data frame and scalebar and the
Best Parcels data frame and scalebar and use Align Left.
Select the City Overview data frame and its scalebar and
use Align Left.
Select the Study Area legend, parcel report, and Highly
Suitable legend and use Align Left.
You may want to double check to make sure none of the
map elements overlap (use the Pan and Zoom tools on the
Layout toolbar) and move any elements accordingly.
Finally, you’ll add two graphic rectangles to make your
map look more polished. The first will frame the title and
North arrow, and the second will tie the entire composition
together.
Adding graphic rectangles
First you’ll place a graphic rectangle behind the title and
North arrow.
1. Click the New Rectangle button on the Draw toolbar.
New
Rectangle
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2. Click below and to the left of the title, in line with the
bottom of the Best Parcels data frame, and drag a
rectangle around the title and the North arrow so the top
of the rectangle is even with the top of the Study Area
data frame.
The graphic rectangle appears on the map but covers the
title and North arrow.
3. Right-click the rectangle, point to Order, and click Send
to Back.
The rectangle is now behind the title and North arrow.
4. Click the dropdown arrow beside the Fill Color button on
the Draw toolbar.
5. Click a light blue from the color menu.
The rectangle is drawn in light blue.
The rectangle should encompass the title and North
arrow. If you need to resize the rectangle, just click one
of its selection handles and drag. If you need to
reposition the title or North arrow so they fit within the
rectangle, just click and drag them.
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PRESENTING THE RESULTS 259
Now you’ll place a second graphic rectangle behind all of
the elements on the page to frame the map and tie the
composition together.
6. Click the Rectangle button on the Draw toolbar.
7. Click at the upper-left corner of the map and drag a
rectangle to the lower-right corner of the map.
The second graphic rectangle appears on the map.
8. Right-click the rectangle, point to Order, and click Send
to Back.
The rectangle is drawn behind the other map elements.
9. Click the dropdown arrow beside the Fill Color button on
the Draw toolbar.
10. Click OlivineYellow on the color menu.
You have completed the poster map for the city council
meeting.
When you produce maps for publication, it is a good idea to
check the final map for errors. This should include
proofreading text, reviewing the symbology to make sure it
is clear, and reviewing the map composition for balance.
You should print the map to verify the colors—this will
also make it easier to do other proofreading work.
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Saving the map and printing it
Now that you have finished laying out the map, you will
save a copy of it. You’ll still have the draft map if you need
to make more changes.
1. Click File and click Save As.
The Save As dialog box appears.
2. Navigate to the project folder.
3. Type “Wastewater Treatment Plant Sites” and click
Save.
Later, when you need to view this map again, it will be
available exactly as you have created it.
If you have a printer connected to your computer, you can
print the map. You created the map as a D size map, so if
your printer will print D size paper, you can print the map at
full size; otherwise, you can scale the map down to fit your
printer.
4. Click File and click Print.
5. If your printer doesn’t print as large as D size, click
Scale Map to fit Printer Paper. If it does print D size or
larger, skip this step.
6. Click OK to print the map.
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PRESENTING THE RESULTS 261
Now you have a map suitable for framing or presenting to
the city council. There were a lot of steps in this fairly
complex map, but as with the analysis phase, you actually
used a small set of operations—in this case, assigning
symbols to features, sizing and positioning map elements,
and adding text and graphic elements. Understanding how
to perform these basic tasks is the key to creating just about
any type of map. Of course, ArcMap gives you many more
options for creating highly customized maps.
The project is finished! The city council is likely to ask for
additional analysis and a new map for their next meeting.
Since the project database is complete, modifying the
criteria and rerunning the GIS analysis should be relatively
easy. And since you’ve saved a copy of your map,
substituting the new analysis results will be straightforward.
You’ve completed a small, sample GIS project. While the
scope was limited, the project process and many of the
specific methods and tasks are ones that apply to a wide
range of projects you’ll encounter in your GIS work. The
next section lists a few of the many resources that are
available to you as you begin to explore the broad range of
GIS applications and the specific functionality of ArcGIS.
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262 GETTING STARTED WITH ARCGIS
This book provided an introduction to usingArcGIS in a
project setting. As you undertake your own GIS projects,
you’ll likely find you may need help with specific tasks
that aren’t covered in this book. You may also need to
employ other ESRI software applications that weren’t used
for this sample project.
This section lists a few of the many resources available for
learning GIS, for finding GIS data and sample maps, and
for getting help. It also provides a brief overview of other
ESRI software applications you may find useful.
Learning GIS
There are a number of resources available for learning
about GIS and learning how to use ArcGIS, including
reference books, workbooks, and courses.
Books
You can use the other books that come with ArcGIS to
learn more about how to use the ArcGIS applications, how
to build GIS databases, how to do GIS analysis, and how to
customize ArcGIS.
When you want to quickly find out how to do a specific
task, you can look it up in one of four reference books:
Using ArcCatalog, Using ArcMap, Editing in ArcMap,
and Geoprocessing in ArcGIS. All ArcGIS books are
available on the ESRI Software Documentation Library
CD. These books are organized around specific tasks. They
provide answers in clear, concise steps. Some of the
chapters also contain background information about the
concepts behind a task. Each book also includes a quickstart
tutorial specific to that application.
If you want task-oriented, step-by-step help creating a
geodatabase, read Building a Geodatabase. This book will
teach you how to take your geodatabase design and
implement it in ArcGIS.
If your job includes designing GIS databases or developing
applications, or if you want to deepen your understanding
of the organization of your GIS, you’ll want to read
Modeling Our World. This book provides a broad
conceptual discussion of GIS data models, with examples
to illustrate the theory.
When you’re ready to explore GIS analysis in more depth,
read The ESRI Guide to GIS Analysis. This book presents
the basic concepts behind geographic analysis. It also
illustrates the most common methods for performing
different types of analysis, using examples from a variety
of GIS applications.
Self-study workbooks
ESRI Press publishes a number of self-study workbooks to
help you learn specific software applications. The books
consist of short conceptual overviews of specific tasks,
followed by detailed exercises framed in the context of real
problems. The books include a CD–ROM containing the
sample data required to complete the exercises. Visit
www.esri.com/esripress for information on currently
available workbooks.
What’s next?
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PRESENTING THE RESULTS 263
Instructor-led courses
ESRI offers more than 35 different courses in various
aspects of GIS, including courses in using, programming,
and customizing ESRI software applications; designing and
building geodatabases; and GIS management. Classes are
offered at facilities throughout the United States and
internationally through ESRI distributors. For course
descriptions, class schedules, and registration information,
visit www.esri.com/training. Outside the United States,
contact your local ESRI distributor for course offerings and
class schedules. To find the ESRI distributor nearest you,
visit www.esri.com/international.
Web-based courses
The ESRI Virtual Campus offers Web-based GIS courses
over the Internet. The courses offer flexibility while
providing hands-on experience and instructional support.
To tour the Virtual Campus and for course descriptions and
registration information, visit campus.esri.com.
Getting information on other ESRI software
There are several ESRI software applications that work in
conjunction with ArcGIS to provide tools for advanced
data analysis and management, including the ArcGIS
extensions, ArcSDE, and ArcIMS®
. What is ArcGIS?
provides an overview of the extensions and applications.
You can also visit www.esri.com/software/index.html to get
more information. Here is a brief description of each.
ArcGIS extensions
Several optional ArcGIS extensions are available for more
advanced analysis and visualization of GIS data.
ArcGIS Spatial Analyst provides a broad range of spatial
modeling and analysis features that allow you to create,
query, map, and analyze cell-based raster data.
ArcGIS 3D Analyst™ enables you to visualize and analyze
surface data in three dimensions.
ArcGIS Geostatistical Analyst lets you create a continuous
surface from sparse measurements taken at sample points.
In addition, Geostatistical Analyst includes tools for
statistical error, threshold, and probability modeling.
ArcSDE
ArcSDE allows you to manage geographic information in
your chosen DBMS and to serve your data openly to the
ArcGIS Desktop and other applications. When you need a
large, multiuser database that can be edited and used
simultaneously by many users, ArcSDE adds the necessary
capabilities to your ArcGIS system by enabling you to
manage your shared, multiuser geodatabase in a DBMS.
ArcIMS
ArcIMS is an Internet mapping system that provides a
framework for centrally building and deploying GIS
services and data. Using ArcIMS, you can deliver focused
GIS applications and data to many concurrent users, both
within your organization and externally on the World Wide
Web.
Finding GIS data and maps
You can complete your GIS projects more quickly and
economically by obtaining existing GIS data, when possible.
Looking at maps others have created using GIS will give
you an idea of the types of projects that are possible with
GIS and ways of visualizing and presenting GIS data, as
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well as possible sources of data for your own projects.
There are a number of sources of both GIS data and maps.
GIS data
Obtaining GIS data for your project can be extremely timeconsuming,
especially if you need to create the digital data
yourself. While you will undoubtedly need to do this for
some proprietary data, there is much existing GIS data
available from many different sources. Base data, such as
streets and elevation, are available from both private and
public sources. In addition, local organizations are finding
it increasingly useful to publish their data for others to use.
The Internet makes finding GIS data much easier than in
days past. Two good places to start are ArcDataSM
Online at
www.esri.com/data/online/index.html and the Geography
NetworkSM
at www.geographynetwork.com. Both sites let
you search for datasets, download free data, license
commercial datasets, and create dynamic maps online.
GIS maps
A good way to see the types of projects and analyses other
users and organizations are doing with GIS is to look at the
maps they create. Each year at the ESRI International
User Conference, users display maps from recent projects
they have completed. Images of many of these maps can
be viewed on ESRI’s Web site, at www.esri.com/
mapmuseum/index.html. Some of these maps are also
published in the annual ESRI Map Book, which is available
online in ESRI’s GIS Store at www.esri.com/gisstore.
Getting support
There are several places to get help with specific issues or
questions while doing a GIS project or to get general
support when getting started with GIS. These include ESRI
technical support, other GIS users, and online resources.
ESRI Technical Support
If you have an issue or question related to a specific
function in ArcGIS and are unable to resolve it using the
documentation or online help system, you can contact
ESRI’s Technical Support Group for assistance. Visit the
ESRI Support Web page at support.esri.com. The site lets
you submit a request for support, search FAQs and other
support documents, download utilities and updates, and
communicate with other users through e-mail lists and
discussion forums.
Support services for users outside the United States are
provided by the international distributor responsible for the
distribution and sales of ESRI desktop software in the
user’s country. To contact your distributor, visit
www.esri.com/international.
Conferences and organizations
One of the most valuable resources you’ll have as you
continue working with ArcGIS is other GIS users. In
addition to providing help with specific technical
questions, users can offer the depth of their experience in
organizational and GIS management issues. A good way to
contact other GIS users in your region or in your field is
through GIS conferences and industry organizations.
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Each year, ESRI holds an International User Conference.
The conference lets users from around the world exchange
knowledge and information, get face-to-face technical
support, and see the latest developments in ESRI software.
For information, visit www.esri.com/events/uc/index.html.
In addition, many local and regional ESRI user groups hold
meetings and conferences several times a year. Visit
gis.esri.com/usersupport/usergroups/usergroups.cfm for
information, or contact your nearest ESRI regional office
or ESRI distributor.
Online resources
There are many online resources in addition to the ones
listed above. A good place to start is www.gis.com. This site
provides general information about GIS and includes links
to other resources, including professional associations
related to GIS, educational resources, sources of GIS data,
and many other resources.
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