Illinois DOQ data have been produced by the US Geological Survey (USGS) via the USGS DOQ program from National Aerial Photography Program(NAPP) photography. Information about the data, along with links to free viewers and plug-ins for the compressed imagery, can be found on the Illinois DOQ Project page. Illinois Digital Orthophoto quarter Quadrangles are available […]
There are 4 major components of IL-GAP; (1) land cover mapping and classification, (2) vertebrate distribution mapping and modeling, (3) land stewardship mapping and categorization, and (4) analysis of the data
Land cover information and data as well as information on the State GAP analysis project
No spatial data here, however, a great directory providing access to Illinois State websites.
Illinois State Geological Survey – Illinois geologic maps, current mapping efforts, USGS topographic maps.
This site is a gateway to GIS data and imagery for Illinois. Available data sets and documentation (metadata) include: DRG files, DOQ data, geology, land use, political boundaries, nature preserves, Public Land Survey, roads, water resources, wildlife areas, year 2000 Orthoimagery for the Des Plaines River Watershed, and Historical Aerial Photographs from 1936 to 1941