Airborne geophysical survey: Maryland Coop '68

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.

航空磁力数据由机载仪器沿飞行航线采集，同步记录磁场强度与位置信息。在早期磁测勘查阶段，此类数据的唯一可视化手段为生成带有等值线的模拟地图。本数据集是对数字化等值线的重构成果：可通过沿等值线追踪采样，或选取等值线与飞行航线的交点来获取磁场强度数值。本次提供的数据包含纬度、经度与地表磁场强度三项数值。