Flights flown between May 6, 1939 and July 11, 1939 by Iowa Aerial Surveys,Inc., for the U. S. Dept. of Agriculture, Agricultural Adjustment Administration. Photos numbered BGH-4-66 through BGH-8-56. Scale not given. Stereoscopic coverage. Only indexes are georeferenced.
Cumberland County (Ill.) (W 88°28′--W 88°00′/N 39°23′--N 39°10′)
Illinois State Geological Survey
242 remote-sensing images, 730 megabytes, average file 3.0 megabytes
Scanned from 7 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.