1. To transform information from one form to another. The distribution may be with respect to variables other than geographic, as ‘‘to map from the time to the frequency domain.’’ Transformations may involve a one point to one point correspondence or one to several (involving multibranched surfaces). Examples of multibranched maps might be the map of a geological formation in the vicinity of a reverse fault where the same formation contact lies at two depths, or a seismic reflection time map in a buried-focus situation where the same reflector can be seen in several directions from the same observation point. 2. The product of such a transformation. The transformation may involve the geographical distribution of observations or of calculations based on observations, as a Bouguer anomaly map or a seismic reflection map. 3. To plot.