Airborne geophysical survey: Elk River ARMS, Minnesota and Wisconsin

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.

本数据集的航空磁测数据由机载仪器沿飞行航线采集，同步记录磁场强度值与空间位置坐标。在早期航空磁测作业中，仅能通过生成带等值线的模拟地图来呈现此类数据。本数据集是对数字化等值线的采样重构：既可以沿等值线轨迹进行采样，也可以选取等值线与飞行航线的交点来获取对应磁场强度数值。本次公开的数据包含纬度、经度以及实测磁场强度三类数据项。