Illinois National Aerial Photography Program (NAPP) Digital Orthophotography quarter Quadrangle (DOQ) data have been created for 96 counties in two projections. These are Illinois Universal Transverse Mercator (UTM) with a NAD83 datum and State Plane (SP) with a NAD83 datum. This data collection excludes the counties of Cook, DuPage, Kane, Lake, McHenry, and Will in northeastern Illinois. Imagery was collected using NAPP specifications using black and white film during the leaf-off period of spring, 2005 at a 1.5 foot by 1.5 foot (half meter) resolution. Programmatic details for Illinois NAPP data were outlined in Illinois GIS Notes, Winter 2005.
|2005 DOQ by Photo Date|
Data files are offered as LizardTech's MrSID Generation 2 .sid files. Target compression ratio is 10:1; one compressed file is roughly 18 megabytes in size.
A statewide collection of both 2005 Chicago Urban Area data and 2005 NAPP (60 Gigabytes) data requires about 100 Gigabytes of storage space. We do not plan to distribute compressed data files by any other means (cd-rom, zip drives, portable drives, ftp download, etc).
An ArcIMS web service has been created for the Universal Transverse Mercator data collections from the original GeoTIFF files loaded into ArcSDE.
Contact theto obtain indiviual, uncompressed Illinois 2005 orthoimagery files. Note that one statewide coverage of uncompressed 2005 Chicago Urban Area data and 2005 NAPP (680 to 690 Gigabytes) data would require about 1 Terabyte of storage space.
Project funding was contributed by:, Illinois Department of Military Affairs, , the , and the .