Airborne geophysical survey: Concord-Denton '57, North Carolina

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（Aeromagnetic data）由机载测量仪器沿飞行测线采集，同步记录磁场强度与位置坐标。在航空磁测工作的早期，此类数据仅能通过绘制带等值线的模拟地图进行展示。本数据集为数字化等值线成果，其生成方式包括沿等值线逐点采样，或选取等值线与飞行测线的交点以获取对应磁场强度数值。数据集包含纬度、经度与测区磁场强度三个字段。