Southeast Illinois '77 (IL)

Survey type M-D (magnetic; collected in digital form)
Flown by TVA
Date flown 06/77-07/77
Line spacing 1.61 (km)
Altitude 304.8 (m) above ground
Total distance 12,231 (km)
References
Counties Clay - Crawford - Edwards - Effingham - Fayette - Franklin - Gallatin - Hamilton - Hardin - Jasper - Jefferson - Johnson - Lawrence - Marion - Massac - Pope - Pulaski - Richland - Saline - Wabash - Wayne - White - Williamson - Gibson - Knox - Posey - Sullivan - Vanderburgh - Ballard - Crittenden - Henderson - Livingston - McCracken - Marshall - Union
Overlapping surveys

Data: Magnetic (M-D)