Eight general types of gravity and magnetic surveys (including gradiometry surveys) are described below. Each type of survey is acquired in a unique operating environment and for a specific purpose. The key to acquiring good quality data, or recognizing the quality of data already in hand, is having a knowledge of suitable survey design and specifications.
The design of a new survey must take into account not only land accessibility (permits, leases, etc), but also terrain conditions and the type, size, and depth of the geologic target. A relatively local target can produce an anomaly with wavelengths from 6 to 24 times the target depth, so the survey bounds must extend outward to cover the anomaly plus some background values. A regional survey should extend outward to some known geologic feature, such as a basin-edge outcrop.