Airborne geophysical survey: Missouri Vertical Intensity Magnetics

Magnetic data were collected by instruments that recorded vertical-intensity
values. Locations were determined by using topographic maps. The best way to
represent this data was to create an analog map with contour lines. This
dataset is a representation of the digitized contour lines by following the
contour lines. The values presented are latitude, longitude, and map vertical-
intensity values.
Note: Only selected parts of the original map were digitized to fill in
around the airborne data.