Stereophotogrammetric Survey

a method of surveying the earth’s surface or other objects from measurements of stereopairs of these objects. The broadest application of stereophotogrammetric surveying has been in topographical surveying—both aerial and terrestrial photographic surveying. Stereophotogrammetric surveying is also used to determine deformations in structures and to study architectural monuments, highway accidents, shore erosion, gully formation, and the movement of glaciers.

The basic processes in an aerial photographic survey are aerial photographic surveying of the locality, geodetic determinations of the coordinates of ground control points, photogrammetric reduction of this network of points to the required density, stereoscopic surveying of relief and contours from aerial photographs, and compilation of a topographic map or chart. Measurements based on photographs for the purpose of reduction and surveying may be made with three-dimensional stereophotogrammetric instruments that reconstruct a geometric model of the locality (the analogue method) or with planar instruments, such as stereocom-parators. In the latter case, the spatial coordinates of points are calculated by computer (the analytical processing method) and either plotted on a chart by means of coordinatographs or stored in digital form (digital models).

In terrestrial phototopographic surveying and in various applications of stereophotogrammetric surveying, photographs of an object are obtained from a fixed base on the ground or from a permanent mobile base, such as a ship. Terrestrial photographs are processed by the same analytical and analogue methods.