A Geographic information system (GIS) is a computer-based tool for mapping and analysis. GIS technology integrates common database operations, such as query and statistical analysis, with mapping techniques. This ability distinguish GIS from other information systems and makes it especially valuable for environmental applications. The Calvin College GIS project involved building a GIS database of the campus using the GIS program AreView. The building of this database involved merging topographic maps, air photos, and AutoCAD files of the campus. Each of these images or files exists in different scales and on different coordinate systems. To convert each image to one common scale, geo-referencing and warping was used. For example, by selecting a known XY coordinate on the AutoCAD file, such as a street comer, one can select the same street corner on the topographic map, finding that map's XY coordinate. Warping makes the topographic point the same as the AutoCAD point, fitting one over the other. Next, each contour line on the newly warped topographic map is traced and give a Z value for elevation. The GIS program reads each point with an XY coordinate and Z elevation value. It then interpolates the surface, assigning values for the entire surface, based on the known XY and Z values. The result is a DEM representing the elevations of Calvin's Campus. The developing Calvin GIS database will serve as a useful integrator of CEAP data on everything from water quality to floristic analysis.
GIS images- click to view them full size
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Internet access to ArcView maps should be available in the future. Stay tuned for Calvin's Campus in GIS.