In this paper, we describe a system for the collection and interpretation of aeromagnetic data. The great interdependence of the detection instrumentation, the navigation instrumentation, the compilation procedures, and the interpretation techniques is defined. Doppler radar is the basis for aircraft navigation; it drives the recording devices to produce spatial-domain data. A digital system provides a means for rapid computer interpretation. A distinction is made between data-processing techniques that aid in interpretation and those that are involved in the actual definition of magnetic anomalies in terms of the horizontal and vertical position of the causative bodies. The computerized interpretation technique described herein is an extension of a technique first described by S. Werner of the Geological Survey of Sweden. Depths are calculated for all geologic events with some elongation, regardless of the events' strike, dip, and remanent magnetization; and the calculations are valid at any magnetic inclination. Our system is illustrated with model studies and actual examples.