Airborne geophysical survey: Southern South Dakota

Aeromagnetic data were collected along flight lines by instruments in an
aircraft that recorded magnetic-field values and locations. In the earlier
days of surveying, the only way to represent this data was to generate an
analog map with contour lines. This dataset is a representation of the
digitized contour lines either by following the lines or by choosing the
intersection of the contour and flight-line to create a value of the magnetic
field. The values presented are latitude, longitude, and map magnetic-field
values.

航空磁测数据由搭载于飞行器的仪器沿飞行航线采集，记录磁场强度与位置信息。在航空磁测的早期阶段，此类数据仅能通过绘制带等值线的模拟地图进行呈现。本数据集为数字化等值线的成果表达，其生成方式为沿等值线追踪采样，或是选取等值线与飞行航线的交点以获取对应的磁场强度数值。所呈现的数据包含纬度、经度以及地图磁场强度数值。