Airborne geophysical survey: Beartooth, Montana

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.航空磁力数据（aeromagnetic data）由搭载于航空器的探测仪器沿飞行测线采集，同步记录磁场强度与位置信息。在航空磁测的早期发展阶段，此类数据唯一的可视化表达手段为绘制带等值线的模拟地图。本数据集为数字化等值线的成果载体，其数据生成方式包含两种：一是沿等值线轨迹进行采样，二是选取等值线与飞行测线的交点以获取对应磁场强度数值。本次公开的数据字段包含纬度、经度与测点磁场强度三项。