Airborne geophysical survey: Olympic Peninsula Offshore, Washington

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）由航空器搭载的探测仪器沿飞行航线采集，同步记录磁场强度与空间位置信息。在航空磁测早期的勘测阶段，此类数据仅能通过绘制带有等值线的模拟地图进行成果呈现。本数据集为数字化等值线的成果转化形式，其生成方式分为两类：一是沿等值线轨迹开展追踪采样，二是选取等值线与飞行航线的交点以获取对应磁场强度数值。本次发布的数据包含纬度、经度与航图磁场强度三类字段。