A passive mapping system employs an antenna or other sensing means having a receiving beam pattern which is scanned in azimuth while moving along a path relative to the area to be mapped. The received signal, after detection and other processing, is recorded on a moving record medium in such a manner that each emitting element in the mapped area generates a straight line of a certain intensity or contrast on the record medium with a slope corresponding to the emitting element range, and the position along the medium corresponding to the location of the antenna along the path. Subsequently, the record medium is processed to collapse or integrate each straight signal line into a point on a further record medium to produce a radiometric plan view map of the area.