Flights flown between June 19, 1940 and July 4, 1940 by Woltz Studios, Inc., for the U. S. Dept. of Agriculture, Agricultural Adjustment Administration. Photos numbered ATCH-1A-37 through ATCH-4A-143. Scale not given. Stereoscopic coverage. Only indexes are georeferenced.
Knox County (Ill.) (W 90°26′--W 89°59′/N 41°09′--N 40°43′)
Illinois State Geological Survey
356 remote-sensing images, 1.25 gigabytes, average file 3.6 megabytes
Scanned from 9 x 9 contact prints (nominal scale ca. 1:20,000) on Crosfield 646IE drum scanning system at 750 dpi. Quality assurance target not published but available by contacting the Illinois State Library Map Dept. MrSID files compressed at a target ratio of 12:1. Uncompressed TIFF images on cd available from the Illinois State Library Map Dept.