Airborne geophysical surveys

Survey name Type Altitude Spacing Flight line distance
DubuqueM/R-D121.9 m 9.60 km2,634 km
Northeast IowaM-A304.8 m above ground1.60 km12,713 km
East-central IowaM-A304.8 m above ground1.60 km12,070 km
Northwest IllinoisM-D548.6 m (barometer)4.80 km2,341 km
SW Wisconsin-NW IllinoisM-D609.6 m (barometer)0.80 km7,563 km
Wis.-Ill. Lead-Zinc '48M-Dz548.6 m (barometer)0.40 km4,441 km