Combined Survey

a type of field topographic work in which the altimetric and planimetric data of the terrain are entered on a photographic map, as a rule in a single unit, simultaneously and immediately on location. In a combined survey, the relief is reproduced in contour lines, using a plane table, on the basis of altimetric transverses and a set of stakes (altimetric points). The contours and ground features are reproduced by decoding their aerial photographic image (when necessary, with additional surveying of individual objects). A combined survey is used instead of a basic (largely laboratory) stereo-topographic survey in making topographic maps of certain forested, built-up, or open flat regions and in making large-scale maps with particularly detailed representation of the relief in areas of land reclamation, mine workings, or planned mining and industrial construction.