Winter 2008

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A GIS map of the United States displays housing densities, one of the factors CALS researchers are using to assess wildfire risks.


1.     GIS is about more than maps—it’s about the meaning behind the maps. Geographic information systems, known collectively as GIS, are probably best known because of online mapping sites such as Google Earth and MapQuest, but they also are essential analytic tools for scientists, public agencies and businesses. These data systems integrate maps with other information, such as traffic patterns, census data or land features, allowing a user to get a picture of how given data relate to location. You might use GIS to find a route to the nearest post office or see where the fish are biting; scientists use it to explore and model patterns in everything from land use to animal migration.

2.     It’s not the same as GPS. Global positioning systems tell you where you are; GIS captures and stores information about the places around you. Here’s a tragic example of why this difference matters: A few years ago, during a brutally hot running of the Chicago marathon, a suburban ambulance came into the city and picked up a victim of heat exhaustion. Although the ambulance had on-board GPS, it did not have a GIS database that could identify the location of the closest hospitals, and the patient died before the ambulance could reach a hospital.

3.     GIS can do more than get you from point A to point B. Some of the most exciting applications of GIS data don’t have anything to do with navigation. Looking at patterns of land use on a map, for example, can help city planners assess the environmental and economic effects of their policies and make better decisions. At CALS, some researchers are using GIS to map urban and wooded areas to characterize wildfire risks.Others are identifying optimal locations for biofuel plants, based on regional feedstock supplies, transportation infrastructure and other factors.

4.     GIS can take you global—or local. While GIS is useful for big-picture assessments, it’s also quite practical for refining small-scale decisions. A GIS can store information about soil conditions across a farmer’s fields, allowing him or her to apply just the right amount of fertilizer in each place. At the same time, GIS can also aggregate data across broad areas to help us understand where fertilizer use contributes to problems such as the “dead zone” in the Gulf of Mexico.

5.     Information can be a double-edged sword. As GIS applications emerge, some people worry that easy access to data about their property might threaten their privacy or security. It’s important to remember that most GIS applications use publicly available data and adhere to strict privacy guidelines. But as with any new information technology, these questions are important to discuss. The more the public participates in the use of GIS applications, the better we can balance information access with protection of privacy and the better we can ensure that GIS is a democratizing influence on public decision-making.

Stephen Ventura is a professor of soil science and director of UW-Madison’s Land Information and Computer Graphics Facility, which conducts GIS-aided research and helps local governments develop GIS applications to aid land use planning

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