Orthophotomap

a photographic map of a locality on an exact geodetic basis. An orthophotomap is obtained through an aerial photographic survey and the subsequent conversion of the aerial photographs from a gnomonic to an orthogonal projection by the efficient method, developed in the mid-1960’s, of differential orthogonal photo conversion. In contrast to the well-known method of converting aerial photographs by zones, the new method automatically eliminates the distortions in an aerial photograph caused by the locality’s relief and by deviations of the camera’s axis from vertical during the survey. This is effected by the successive projection of the image being converted in the smallest possible sections by means of special devices called orthophotoprojectors. Orthophotographs, that is, aerial photos converted by this method, make possible the compilation of orthophotomaps for any region, thus significantly expanding the use of material from aerial photographic surveys for topographical, geological, and other planning and surveying purposes.