1192 S. Tooth
Copyright © 2006 John Wiley & Sons, Ltd. Earth Surf. Process. Landforms 31, 1192–1194 (2006)
DOI: 10.1002/esp
Earth Surface Processes and Landforms
Earth Surf. Process. Landforms 31, 1192–1194 (2006)
Published online 30 May 2006 in Wiley InterScience
(www.interscience.wiley.com) DOI: 10.1002/esp.1383
ESEX Commentary
Virtual globes: a catalyst for the re-enchantment
of geomorphology?
Stephen Tooth*
River Basin Dynamics and Hydrology Research Group, Institute of Geography and Earth Sciences, University of Wales, Aberystwyth, SY23
3DB, UK
Received 6 March 2006; Revised 19 March 2006; Accepted 27 March 2006
*Correspondence to: S. Tooth, River Basin Dynamics and Hydrology Research Group, Institute of Geography and Earth Sciences, University
of Wales, Aberystwyth, SY23 3DB, UK. Email: set@aber.ac.uk
Baker and Twidale (1991) bemoaned a perceived loss of enchantment from the discipline of geomorphology, arguing
that practical and philosophical impediments were thwarting attempts to achieve a satisfying understanding of landforms
and their genesis. Other concerns for the status and future of the discipline have been voiced subsequently, most
recently in this forum (e.g. Church, 2005; Summerfield, 2005a), and have highlighted challenges such as the relationship
of geomorphology to cognate disciplines, difficulties in reconciling teaching and research needs, the balance
between pure and applied studies, and the undertaking of landscape studies by researchers from outside the traditional
geomorphological community. The purpose of this commentary is not to deny these challenges but to echo Summerfield’s
(2005a) cautiously upbeat tone, by proposing that a more positive development is the recent launch of virtual globes
that vastly increase the availability of digital imagery of the Earth’s surface, and thus provide an opportunity for the
re-enchantment of geomorphology.
Virtual Globes
Virtual globes such as Google Earth and NASA’s World Wind combine topographic representations of the Earth’s
surface with satellite imagery. Using simple controls, one can zoom from altitude to any natural or urban area, and
using a combination of zoom, pan and tilt, examine the terrain at different scales from vertical or oblique, threedimensional
(3D), perspectives. Google Earth has one layer of relatively recent (last three years) satellite imagery
stitched together from a variety of commercial sources, whilst World Wind has multiple layers of satellite imagery
(e.g. LandSat 7, SRTM, MODIS), as well as topographic maps for the United States. Both programs have higher
resolution imagery for some cities and areas of North America and western Europe. Images are fully georeferenced,
with options to display relevant coordinates, spot elevations and place names. These facilities have long been available
in expensive GIS software packages, but the basic versions of virtual globes are available free on the Internet, can be
downloaded and installed in a few minutes, and will run smoothly on most modern computers with a fast internet
connection. Thus, with minimal technical ability and a few mouse clicks, virtual globes can bring the varied
geomorphology of Earth into one’s office or home, and associated animations and overlays can be used to visualize
landscape-scale events such as hurricanes, wildfires, floods and dust storms. Virtual globes for other planetary bodies
such as the Moon and Mars are available as add-ons for World Wind, and interactive image mosaics are also available
via Google Mars and Google Moon. Unsurprisingly, virtual globes have been capturing the imagination of scientists
and laypeople alike; in its first week on the web (late summer 2004), 100 000 users downloaded World Wind (NASA,
2004), and millions more have downloaded virtual globes since. World Wind is an open source program, enabling
users to contribute their own modifications, and Google Earth allows user modification within certain pre-defined
parameters. As reported in Nature (Butler, 2006; Nourbakhsh, 2006), researchers in other disciplines have already
seized upon the potential of virtual globes to display a variety of spatial data in order to enhance basic scientific and
applied work. No doubt many geomorphologists have also considered the possibilities; indeed, when a colleague
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Copyright © 2006 John Wiley & Sons, Ltd. Earth Surf. Process. Landforms 31, 1192–1194 (2006)
DOI: 10.1002/esp
(T.S. McCarthy) introduced me to Google Earth during a visit to Johannesburg last summer, its potential for geomorphological
research, teaching and outreach immediately seemed considerable, as outlined below.
Potential Use of Virtual Globes in Geomorphology
Geomorphological research involves a variety of approaches, including field mapping and monitoring, laboratory
analyses, physical modelling and numerical modelling. In some cases, virtual globes may usefully supplement these
approaches. In particular, by enabling 3D terrain visualization, and by explicitly focusing attention on issues of spatial
pattern and scale, they may provoke hypotheses about landscape form and process that can be investigated further
using one or more approaches. They may aid fieldwork planning, particularly in terms of sampling design, and local
field observations and measurements can be placed more effectively in their broader spatial context. Without virtual
globes, similar attempts to assess these spatial issues are often possible only through purchase of aerial photographs or
satellite imagery, which are sometimes difficult to source, are often expensive, have fixed resolution and perspective,
and are physically unwieldy if large areas are being considered. The advantages of virtual globes in terms of ease-ofuse
and time saving are clear. For instance, researching river pattern variability across central Australia once took
weeks of sifting through aerial photographs in storerooms, but using the spatially searchable, interactive interface of
virtual globes, this can now be accomplished more effectively in a few afternoons from my office. Similarly, researching
gully distributions in South Africa previously has been hampered by limited aerial photograph coverage or
mapping inconsistencies between topographic sheets, but gully locations can now be determined with ease, thus
providing an enhanced knowledge base from which to hypothesize about controlling factors. Ideas can be discussed
more effectively with distant colleagues by supplying grid references relating to landscape features that they can view
with a few mouse clicks on a virtual globe. Reviewers of papers based on some types of field-based research will also
benefit, for they can now view the study area, improving their ability to visualize the landforms being described, and
perhaps enabling them to challenge interpretations of data in ways not possible previously.
For teaching and outreach, the power of 3D visualization and spatial awareness provided by virtual globes cannot
be underestimated. Even the most uninterested student finds it hard not to pay attention during oblique fly-overs of
distinctive landscapes such as the dunefields and playa complexes of the Simpson Desert, the Grand Canyon of the
Colorado River, the glacial landscapes of the European Alps, or the coastal scenery of New Zealand’s Fiordland.
Unfamiliar landscapes can be brought into the lecture room in ways that are simply not possible with static slides
or photographs taken from fixed perspectives, and familiar landscapes can be seen from new perspectives, provoking
more informed contemplation about processes and controls. Key geomorphological concepts, such as scaledependence
of controls, can be illustrated by examining regions or features at different scales. For example, in
some sand seas, virtual globes can rapidly demonstrate that at large spatial scales, linear dune orientations tend to be
related to regional air circulation patterns, but at smaller scales, other factors start to assume greater importance,
with dune orientations commonly adjusting in response to wind and sand transport changes resulting from local
topographic forcing. Furthermore, as some researchers have long suggested (e.g. Baker, 1993), imagery available for
other planetary bodies can be used to enhance understanding of Earth’s processes and landforms. For instance, using
virtual globes to view heavily cratered regions of the Moon or Mars immediately begs the question as to why
craters are less numerous and less well preserved on Earth, which leads on to consideration of the role of plate
tectonics in recycling large parts of the Earth’s crust, and the influence of subaerial processes on landscape denudation.
Innovative use of such approaches in teaching and outreach can only enhance appreciation of geomorphology.
Limitations of Virtual Globes in Geomorphology
Virtual globes are not without limitations. For many (possibly most) geomorphologists, the potential research advantages
may appear trivial, so perhaps their value is more for teaching and outreach. With the present generation of
virtual globes, satellite image quality is variable from area to area; spatial resolution is often sufficient for detailed
examination only of macro-scale geomorphological features, and images are often several years old and may not have
been taken at optimum times for geomorphological analyses (e.g. when high water levels obscure some landforms).
Quantitative measurements of key parameters (areas, slopes) are not possible without recourse to additional software
and digital data sets (e.g. DEMs). There is also the risk, common to existing remote sensing imagery and GIS
software, that virtual globes will simply be used to generate visually appealing imagery without any corresponding
advancement in the understanding of geomorphological process and form, particularly because the vital fourth dimension
(time) is missing. Nevertheless, the ease of use of virtual globes may well encourage researchers to explore more
1194 S. Tooth
Copyright © 2006 John Wiley & Sons, Ltd. Earth Surf. Process. Landforms 31, 1192–1194 (2006)
DOI: 10.1002/esp
powerful, analytical GIS techniques (Butler, 2006) and, coupled with developments in other areas of the discipline (e.g.
increasing use of cosmogenic isotope analysis to quantify process rates and landscape denudation rates), virtual globes
can only help promote the recent heightened level of interest in macro-scale landform development outlined by
Summerfield (2005a, b). With potential for further technical developments (e.g. higher image resolution, more
frequent image updates), and incorporation of innovative visualization of environmental phenomena relevant to geomorphological
processes (e.g. 3D fly-bys of weather systems; Butler, 2006), virtual globes can only benefit the discipline.
Enchantment, Disenchantment, Re-enchantment?
‘Enchantment’ in geomorphology could be defined in various ways but surely involves stimulating interest and
excitement in landscape form, process and change, and provoking the all-important reflective questions such as
‘why?’, ‘how?’ and ‘when?’. Baker and Twidale (1991) argued that the Golden Age of the scientific study of landforms
was during the late nineteenth century, when curious, even astounding, tropical and arid region landscapes were
investigated by scientist explorers more familiar with the humid temperate landscapes of northwest Europe and
northeast North America. The creative thinking stimulated by these new landscapes led to theory development that
expanded and improved explanations for already-familiar landscapes. As the twentieth century progressed, however,
fascination with landscapes was gradually replaced by a sense of disenchantment as geomorphology tended to overemphasize
methodology, either for theoretical abstraction or ‘objective’ measurement, and geomorphological study
became more remote from the realities of the Earth’s surface that constitute its raison d’être. Baker and Twidale
(1991) provided their prescription for the ‘re-enchantment’ of geomorphology, in particular arguing that there was a
need for a new intimate association between the scientist and landscape, unfettered by overly restrictive theorizing,
that would facilitate identification of anomalies in landscapes and formulation of ‘outrageous’ hypotheses of causation.
They cited fringe areas of the discipline (planetary geomorphology, tectonic geomorphology, study of ancient
palaeosurfaces) as examples of where some of the most exciting geomorphology is being conducted.
For many geomorphologists, Baker and Twidale’s (1991) prescription undoubtedly continues to be regarded as
unpalatable or unnecessary. Outside the aforementioned fringe areas, relatively few geomorphologists have taken the
medicine, instead preferring to focus study efforts on more detailed physics-based or mathematical treatments of
processes, commonly (but not necessarily) at smaller spatial and shorter temporal scales. Pluralism in study approach
and focus should be regarded as as a sign of a healthy, active discipline rather than as a sign of division, although
clearly greater efforts are needed to encourage interaction between communities of researchers working at different
scales if the discipline as a whole is to reap the benefits (e.g. Summerfield, 2005b). If one accepts that the ultimate
goal of geomorphology is to understand the present spatial distribution and interrelationships of Earth surface
phenomena at different scales, and to provide explanatory accounts of landscape development through time (cf. Baker
and Twidale, 1991), then emphasis on phenomena over larger areas and at longer timescales must constitute a vital
part of this collective effort, and virtual globes can facilitate this. Public interest in Earth’s landscapes is high, as
evidenced by the popularity of virtual globes, yet the term ‘geomorphology’, and what the scientific study of landscape
entails, is understood by relatively few. By harnessing the power of virtual globes in research, teaching and
outreach, can this act as a catalyst for the re-enchantment of geomorphology? Will this encourage renewed fascination
with landscapes, and thus promote geomorphology as a worthwhile, valid and distinctive study endeavour? Will this
lead to more hypotheses regarding landform genesis that could be tested by field, laboratory or modelling approaches,
perhaps extending and/or replacing prevailing concepts and theories? Whilst clearly not a panacea, will this help to
counter or circumvent some of the challenges that the discipline faces?
References
Baker VR. 1993. Extraterrestrial geomorphology: science and philosophy of Earthlike planetary landscapes. Geomorphology 7: 9–35.
Baker VR, Twidale CR. 1991. The reenchantment of geomorphology. Geomorphology 4: 73–100.
Butler D. 2006. The web-wide world. Nature 439: 776–778.
Church M. 2005. Continental drift. Earth Surface Processes and Landforms 30: 129–130. DOI: 10.1002/esp.1183
NASA. 2004. NASA computer program is hot download on the internet. Available at: www.nasa.gov/vision/earth/environment/
World_Wind.html [28 February 2006]
Nourbakhsh I. 2006. Mapping disaster zones. Nature 439: 787–788.
Summerfield MA. 2005a. The changing landscape of geomorphology. Earth Surface Processes and Landforms 30: 779–781. DOI: 10.1002/
esp.1183
Summerfield MA. 2005b. A tale of two scales, or the two geomorphologies. Transactions of the Institute of British Geographers NS 30:
402–415.