MODELLING: GIS
Finding the ‘science’ in GIS
While popular services such as Google Earth and Bing Maps have made basic geographical information system functionality well-known, scientific investigations need considerably more power. Paul Schreier maps the highlights of the GIS product landscape
Who among us hasn’t used Google Earth or Bing Maps (previously Microsoft Virtual Earth) to take a look at our homes, neighbourhoods or interesting structures? From our desktops we have access not just to street maps, but now aerial and satellite imagery, 3D city models and terrain. These services also make it easy to overlay your own data points or layers to highlight concepts. In just the past year or two, such web services have driven incredible awareness and usage geospatial technologies and applications among the general public. Welcome to the world of GIS: geographic
information systems. An oversimplified definition would be ‘plotting data on maps to make it easier to spot patterns or trends’, but that’s just scratching the surface of what fully- fledged GIS systems really do. Instead, realise that a GIS is a platform
for capturing, managing, manipulating and visualising geographic information. This platform technology brings together information from many fields and sciences – physical, social, cultural and design – and integrates the resulting geographical knowledge across disciplines through mapping and modelling of spatial relationships and patterns. GIS is the glue that integrates many different types of data. It allows you to see data on a map and analyse it to reveal patterns, relationships and trends not readily apparent in tabular data. Without GIS it would be almost impossible to collect large volumes of information about
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observable events, and then build and test theories about patterns and processes. Or, to summarise all this in the words of Steve Kopp, lead software developer for scientific tools at ESRI, ‘GIS is basically creating new data from data you already have. The traditional role of GIS is finding the best place to put something or find something, and very similar techniques also apply to scientific applications.’ GIS has long been used by governments for
urban planning and by utilities (for example, where does one place mobile phone antennas to get the best coverage?). In the sciences, GIS is gaining use in diverse areas, examples being global climate change, solar panel placement and efficiency studies, epidemiological studies, oil/gas exploration – and even archeology.
The public face of GIS
The most visible manifestation of GIS is mapping, and this aspect has come to the forefront through free web services. In this regard, consider Google Earth, a service originally called EarthViewer 3D created by Keyhole, which was acquired by Google in 2004. The free version lets you take an aerial view, save locations, and share them with others. Businesses using it for external purposes must license Google Earth Pro, which also allows GIS data import, high-res printing and radius/area measurements. Google Earth Enterprise is intended for organisations with their own large geospatial databases; designed to run on a company’s own servers, it gives an entire organisation access to Google Earth. While Google Earth has a convenient interface for simple operations, many users automate procedures using the Keyhole Markup Language (KML). This is an XML language maintained by the Open Geospatial Consortium (OGC) and can be used with internet-based 2D maps and 3D Earth browsers from many sources. It is focused on geographic visualisation, including annotation of maps and images. With a few lines of code you can set placemarks, while other KML functions handle ground overlays, paths, and polygons. Services such as Google Maps provide low-
Built around ArcGIS Server, this web-based application by the Amazon Initiative, showing deforestation projections, illustrates only a few custom features users can build into GIS maps.
cost, easy access to geographical information – and, in some ways, have redefined the boundary of what GIS is, says David Maguire, pro vice- chancellor at Birmingham City University, and former chief scientist at GIS software house ESRI. Google Maps does simple things simply with low-cost basemaps, through which people can observe the world. He adds that it has brought in a massive user base and sent shockwaves through the GIS industry. However, if Google and Microsoft were to do these things as a standalone company, they’d be broke; instead, they use these services as ‘megamarketing tools’ to drive their other businesses.
SCIENTIFIC COMPUTING WORLD APRIL/MAY 2010
www.scientific-computing.com
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