Flight flown July 7, 1939 by Midwest Aerial Surveys, Inc., for the U. S. Dept. of Agriculture, Agricultural Adjustment Administration. Photos numbered BXD-1-21 through BXD-2-127. Scale not given. Stereoscopic coverage. Only indexes are georeferenced.
Menard County (Ill.) (W 90°00′--W 89°35′/N 40°10′--N 39°54′)
Illinois State Geological Survey
123 remote-sensing images, .76 gigabytes, average file 6.38 megabytes
Scanned from 9 x 9 contact prints (nominal scale ca. 1:20,000) on Crosfield Celsis 6200 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 6:1. Uncompressed TIFF images on cd available from the Illinois State Library Map Dept.