Definition

A series of marks or GRADUATIONS at definite intervals. The ratio between the linear dimensions of a CHART, MAP, drawing, etc., and the actual dimensions represented. It may be called chart scale or map scale when applied to a CHART or a MAP. In PHOTOGRAMMETRY, the ratio of a distance on a PHOTO­GRAPH to a corresponding distance on the ground. The scale of a PHOTOGRAPH varies from point to point becau­se of DISPLACEMENTS caused by TILT and RELIEF; but it is usually taken as f/H where f is the PRINCI­PAL DI­STANCE of the CAMERA and H is the HEIGHT of the CAMERA above mean ground elevation.