Airborne geophysical survey: Modoc East, 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.航空磁测数据（aeromagnetic data）由机载仪器沿飞行航线采集，同步记录磁场强度值与位置信息。在勘测早期，此类数据唯一的可视化方式为生成带有等值线（contour lines）的模拟地图（analog map）。本数据集为数字化等值线的成果呈现，其数字化流程可通过两种途径实现：沿等值线追踪采样，或选取等值线与飞行航线的交点以获取对应磁场强度数值。本数据集包含的参数为纬度、经度与图载磁场强度值。