An instrument for drawing topographic maps from observations of stereoscopic aerial photographs with a stereocomparator.



a high-precision general-purpose ste-reophotogrammetric instrument for making topographic maps and charts by means of optical projection.

Figure 1 shows a diagram of a stereoplanigraph. The guides X, Y, and Z reproduce a rectangular coordinate system; guides X and Y are fixed, and guide Z moves along guide Y. Two cameras (2), constituting the instrument’s basic projection system, are mounted on a carriage (1), which moves along guide Z. Each camera is able to turn by angles α and ω, which correspond to the angular elements of orientation of the photograph.

The stereoplanigraph has a set of cameras with lenses capable of focusing to various distances. Photographs are positioned in the focal planes of the lenses and can rotate by angles K. Measuring marks (3) have the movement bx, by, and bz for fixing the projection base length.

Figure 1. Diagram of a stereoplanigraph

In operation, the marks move in the plane XY, and the cameras move in the direction Z; thus, the distances between the marks and the cameras change. A supplementary projection system placed immediately behind the lenses is used here to preserve the sharpness of the image. This system is controlled by special gauges mounted on bars.