Spatial conflicts
 Pre
 Congestion - the crowding of features
 Coalescence - features are indistinguishable
 Self-coalescence – spikes or similar
 Conflict - feature symbology overlaps
 Imperceptibility – feature or its part is too small at
given scale
 Post
 Complication – topological inconsistency
 Inconsistency - features are wrongly transformed
differently under similar cartographic conditions
Identification of Spatial
conflicts
 Congestion – graphic fill measurement
 Coalescence – hausdorffian distances
 Conflict – buffers and overlays
 Imperceptibility – SVO theory
 Complication – shape validation, relationships
validation
 Inconsistency – shape measrement
Graphical filling
 Max. 30 mm2/100 mm2 of map face
 Active parts of symbols
 GF = (Σqi x ri x αi)/106
x S
 S is scale denominator
 Qi is density of i-type features on 100m2
 Number or total length
 Ri is area per unit in map in mm2
 αi coefficient of selection max=1
Hausdorffian distances
 Separability of two features
 For points identical with Euclidean distance
 Basic form is max from min distances
 Extended form includes
 Descriptive statistics of distances
 Identification of closest parts
 Often used also for text placement
SVO parameters
 0.02 – 0.08 mm black lines
 0.1 mm colour lines
 0.2 mm area distance
 0.4 - 0.7 mm min. side of rectangular shape
 0.2 mm min. side of inner area
 0.4 – 0.7 mm min. bend base
 0.4 mm min. bend height
Conflict solution
 Complex issue
 But first steps are
 Selection
 Omition
 Resymbolization
 Two questions
 How many – Topfer law
 What – not so easy
Extended Topfer law
 Nf = Na * Cb * Cz * sqrt(ma/mf)
 Na – source feature number
 Cb - significance of feature class
 Cz – ratio between symbols
 Ma - source scale denominator
 Mf - outcome scale denominator
Extended Topfer law
 Cz = Sa/Sf * sqrt(Ma/Mf) where
 Sa – source width
 Sf – final width
 Cz is equal 1 if ratio of symbols is proportional
to scale change
 Cb is equal to
 1 for normal significance
 sqrt(Mf/Ma) for important feature class
 sqrt(Ma/Mf) for less important class
What select or omit
 Always combination of parameters
 Geometric – various descriptive statistics, structure
identification
 Semantic – importance of feature and preserving
character of AoI
 Developed areas
 Settlement – theories of influence
 Roads – shortest path combinations
 Rivers – stream orders
 Terrain skeleton - geomorfometry
Iterative generalisation
 Preprocessing
 Feature hierarchy
 Incremental modules
 Price of operation
 Generalization scheme
 Hardcode of generalization preprocessing
results
 No simulation of man-made generalization
 Hierarchy of constraints
Preprocessing &
Feature hierarchy
 TVM
 To remove redundant vertices
 To distinguish artificial and natural features
 To unify vertices order
 Cluster features
 Topography
 Terrain
 Thematics according purpose
 Usually 3 levels of importancy
Incremental modules
 Landscape skeleton
 Terrain lines
 Important rivers
 Important communications
 Administrative division
 Keep crossing of
 Important rivers
 Important communications
 Urban blocks
 Road network