GIS TO GEOWALL: HARNESSING 3D VISUALIZATIONS

The Geowall (www.geowall.org) provides a simple, low-cost platform for 3D graphics visualizations. The Geowall uses two projectors for virtual reality. Existing software consists primarily of viewers, designed to display and manipulate 3D models created by other software. We have integrated two Geowall viewers (Immersaview and Walkabout) with a powerful, easy to use, and free GIS (MICRODEM). MICRODEM allows easy, graphical selection of map areas and display of digital elevation models (DEMs), satellite imagery, orthophotos, scanned maps, and vector shape files and TIGER line data. For export to the Geowall, MICRODEM produces a VRML file with the terrain mesh and one or more image textures to drape on the terrain mesh. MICRODEM then opens either Immersaview or Walkabout for immediate 3D interaction with the terrain. The two programs display different and complementary views of the terrain. Immersaview displays 3D surface diagrams with the capability to rotate and zoom. Walkabout supports the exploration of scenes containing dynamic objects, 'walking' topographic surfaces draped with maps and remote sensing images. Immersaview and Walkbout run on the Windows, Linux, and Mac operating systems, but MICRODEM only works on Windows. However, the VRML and texture files created by MICRODEM can be displayed on other operating systems. In addition to stereo viewing on the Geowall, Immersaview and Walkabout both allow single-monitor 3D scene manipulation. All three programs are available for free download at www.evl.uic.edu/cavern/agave/immersaview/, www.evl.uic.edu/aej/macagave/walkabout.html, and www.usna.edu/Users/oceano/pguth/website/microdem.htm. Much of the power of these 3D visualizations lies in having multiple textures, such as scanned topographic maps, geologic maps, satellite imagery, or overlays created from the DEM such as slope or topographic shading. Rapid switching between textures shows the multiple relationships among parameters.