Airborne geophysical survey: Sierra Nevada '63 Central, California

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.

本数据集的航空磁力数据（aeromagnetic data）由搭载于航空器的探测仪器沿飞行航线采集，同步记录了磁场强度与位置信息。在早期航空磁测工作中，此类数据唯一的可视化手段为生成带等值线的模拟地图。本数据集通过两种方式实现数字化等值线的还原：一是沿等值线轨迹采集数据点，二是选取等值线与飞行航线的交点以获取对应磁场强度值。所记录的数值包含纬度、经度以及图载磁场强度值。