Some geographers are getting very excited over the uses of computerised mapping systems. Others are not convinced. John Davies reports. Cartographic wonder-tool or overhyped techical gizmo? Enhancer or distorter of reality? Geographical Information Systems, generally known as GIS, have been available to academic researchers for some 20 years, but now more than ever their use is a matter of controversy. There is talk of a divide opening up in geography between the quantifiers and the cultural theorists - between, in Leeds geographer Stan Openshaw's words, the "doers" and the "watchers".

What then is GIS? To quote Southampton University's David Martin, it is "a special type of information system, concerned with the representation and manipulation of a model of geographic reality closely related to computer assisted mapping and satellite image processing systems".

The end point of GIS, then, is new maps - maps of all kinds, displaying anything from income distribution to gas pipes, from bird migration to the rate at which a glacier might melt. Traditional map makers are changing too: the Ordnance Survey has now digitised all its data using GIS, enabling it to create customised maps as required.

"GIS is a major technological improvement which both allows lots of things to be done much easier than before, and also allows you to do things it would have been nice to do before but which you could never do," says Ron Johnston, former vice-chancellor of Essex University and now professor of geography at Bristol. "If you've got a data set and you're not sure how to map it, you can try all sorts of ways in miniature (using GIS). Whereas before it took hours to draw one map and then you maybe didn't like it."

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Johnston's speciality - political geography and in particular the drawing of parliamentary boundaries in Britain - has certainly benefited from the GIS revolution. The Boundary Commission's recent redrawing of the constituency map was done with the help of GIS, "and as a consequence", says Johnston, "they've done a much better job of producing maps to meet the criteria that constituencies should be as equal as possible."

Nevertheless, Johnston adds, "we all get carried away by our own obsessions, and some of the people who have taken time to master this new technology make rather grandiose claims".

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Peter Taylor, professor of geography at Loughborough University, widens Johnston's critique. "GIS is a very practical, useful tool," he says. "But the most interesting thing about tools is how to operate them: who has control of them, who benefits from them."

Inevitably, GIS inhabits a commercial as well as an academic sphere. And its critics have characrtised some commercial applications as tools used by powerful corporations against dehumanised consumers. (McDonald's uses a GIS of human traffic patterns to predict the best locations for future hamburger outlets.) What is more, in the United States, many GIS developments have been stimulated by defence department needs. In Ground Truth, a collection of critical essays about GIS, the University of Hawaii's John Goss writes: "Information technology and computer assisted cartography were developed partly under generous assistance from the military which saw in them potential applications for military intelligence." He adds: "Indeed one of the most publicised 'successes' I has been their application in decision support in the Gulf war."

"What of it?" would be the response of a GIS enthusiast such as Stan Openshaw, professor and director of the centre for computational geography at the University of Leeds. "People point out GIS was used in the Gulf to kill Iraqis. But it's not the technology that's evil, it's what people do with it. After all, maps have always been used as a military device."

Openshaw believes there is "a sort of schism between the watchers and the doers" in geography. He traces it back to the "quantitative revolution" in the 1960s and 1970s, when statistical methods were imported into the discipline from the sciences. "Everyone got very excited about it, but most of the benefits promised didn't materialise. At the same time some geographers were discovering other philosophies - humanism, Marxism, postmodernism - and therefore moved away from quantitative geography and tended to deride it.

"The irony was that just at the moment when that movement reached its peak, along came GIS - which put great emphasis on all the things antiquantitative geographers hated most, like drawing maps, like using spatial information to make decisions."

Openshaw's schism is "between those who see geography as being applied geography - trying to solve problems in the world by using geographical technology to make it a better place - and those who would rather use geography to watch the world in operation.

"People persist in saying 'Your data are not quite right'. Of course not, but we've now got the technology to cope with it being not quite right. We've got new technologies in the form of artificial intelligence: there are new computing paradigms based on soft computing that handle non-numeric information. The world's changed dramatically, and the sad thing is that some human geographers (such as some of the contributors to Ground Truth) are still living in the late 1970s."

This is not how Loughborough's Taylor would see it. "Some writings on GIS have tended to offer a naive whiggish theory of technology I The idea is: we'll supply better techniques and the world will become a better place. That sort of ideology - which I thought had disappeared - has been lurking in some GIS."

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Taylor contrasts GIS with "what I call GKS - geographical knowledge systems". Information is not the same as knowledge or understanding, he continues: "GIS deals with units of information and sometimes loses the overall framework".

Such units of information, he warns, must be treated with caution. "Statistics tend to be generated by states - they're state-istics if you like. The image of the world that's produced by statistics and by people who analyse statistics is a state-centric view. But how can we grasp things like globalisation in culture or economics, or environmental issues? These things are extremely resistant to being accommodated by states and therefore aren't necessarily well represented in statistics."

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Environmental modelling, another use for GIS, also needs to be exercised with caution, says Stephen Carver, one of Openshaw's Leeds colleagues (see panel). "You can take vegetation and topography and put it on to a spatial context by linking it with GIS," he says. "That's all well and good, but it depends on the accuracy of your data to start with, and also the working of your model." Or as Southampton University's Martin puts it: "You can only get as good an answer as the numbers that are put in."

Martin, described by John Pickles in Ground Truth as "unashamedly boosterist" for GIS, a label he feels he does not deserve, is equally keen to emphasise the system's limitations. Geographic information systems, he continues, "do not in any sense provide a definitive objective model of geographic 'reality'."

Martin also talks of the difficulty that GIS has in dealing with temporal data and he admits to failure when his Southampton oceanography colleagues sought to use GIS in modelling tides and water quality in the Solent. "There is nothing within the current technology that can cope with the idea of a continuous time I apart from having a different data layer for every day of the year, which would be prohibitively expensive."

At the environmental systems science centre in Reading University's geography department, Gary Robinson would agree. He goes as far as describing GIS as "stuck in a rut"; it is, he says, "great for doing social statistics, but not for evolving processes. For instance, GIS won't do to model what happens if a nuclear reactor explodes. I think of it as a bit passe. It's just so tied to maps, to the two-dimensional."

Openshaw, though, is not disheartened. "It's a challenge. The GIS revolution has emphasised mapping but not modelling I We're drenched in information now; you can get vast data sets with very good, accurate geography, but no one knows what to do with them apart from draw maps. Take health data: we may have information about children who have got some horrible disease - where are the patterns? What relationships are there? The technology needed to answer those sorts of questions is still in its infancy.

"For me, that's the task of academic geographers. Rather than complain about the misuse of information or worry about the data not being precisely accurate or about the social inequalities the use of technology may or may not be creating, they should be getting down to tackling these fundamental challenges like what new models we need. They should be getting on trying to develop some of the existing technology."

HOW GIS CAN WORK IN PRACTICE

In Russia's Altai mountains, near the borders with Kazhakstan and Mongolia, an expedition led by Ian Heywood of Manchester Metropolitan University has used GIS for various field work projects.

"It's a largely unspoilt wilderness area," explains Heywood's expedition colleague Stephen Carver, of Leeds University. But the region, which has a nomadic population, has recently seen a rise in the number of tourists and as a result, walking, skiing and whitewater rafting have grown and campsites with their attendant rubbish dumps have proliferated."So the Russians are thinking of setting up a national park in the area," continues Carver, "and we went to gather data on the physical environment and to look at the human impact."

The British expedition team, which was joined by geographers from the local Altai State University, had little in the way of detailed maps.

"The Russians are still into traditional cartography," says Carver. "They spend years and years collecting data and then at the end of the day they have this beautiful hand-drawn map which is a static resource. You can't do much else with it - you can't integrate it with other data."

The GIS represented something dynamic, something that could be updated. "The idea was to go out every day gathering data, come back and feed it into the GIS and incrementally create new maps. The water scientists, the vegetation scientists, the sociologists who had interviewed people in the field and so on - they would use it as a catalyst for discussion in the evenings.

"When you've got some material on the computer screen, everybody's interested in their own thing, but you can overlay it with someone else's work, and then the ideas start flowing."

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