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Photogrammetrical Methods of Topographical Mapping in Use in the 
U.S.S.R. 
by M. D. KONSHIN 
U.S.S.R. 
Proceeding from the necessary to our country rate of mapping, a differential method 
of aerial stereophotogrammetry has been chosen as the principal method of mapping flat 
and hilly regions at the scale 1:100,000, the said method being based on utilization of 
topographie stereometers. These instruments secure an accuracy of terrain representation 
about H : 2,500 which is quite satisfactory from the point of view of the precision require- 
ments to maps at the scale 1 : 100,000. A method of plotting from super-wide-angle photo- 
graphs with the aid of these instruments was proposed. In the case of topographical map- 
ping of mountainous regions stereophotogrammetrical plotting was executed on the 
multiplex. 
In every region aerial surveying was carried out with single-lens superwide-angle 
aerial cameras; plotting was executed by stereophotogrammetry, and various photogram- 
metric methods of horizontal and vertical control extension had found application. The 
extension of horizontal control in mountainous regions was executed on a multiplex 
provided with a sufficient number of projection cameras, whereas in flat and hilly regions 
this was done by a graphical method of radial triangulation with the radial centres at a 
conventional nadir point (the true nadir point being unknown). After the technique of using 
the radio-altimeter had been elaborated, the extension of horizontal controlin flat and hilly 
regions was done by photopolygonometry which permits to increase the extent of photo- 
grammetric framework. 
The photogrammetric extension of vertical control was accomplished on a multiplex 
or by various analytical means, because the utilization of universal first-order stereophoto- 
grammetric instruments was not feasible at that time owing to the fact that aerial 
surveying was executed with superwide-angle cameras. It was only after the method of 
plotting from aerial photographs with transformed ray-bundles had been worked out that 
the use of universal instruments was rendered possible, although the solution of the problem 
in the case of large angles of tilt in the photographs and of great differences of terrain 
elevations proved to be rather complicated. Vertical control extension was often executed by 
radio-levelling, the data of the latter being adjusted simultaneously with photogramme- 
trical data. At present, large-scale and medium-scale topographic maps are produced in the 
USSR following a slightly modified method. The present day method of topographic map- 
ping in large and medium scales is based upon the following fundamental principles: 
1. The principal method of topographic mapping is stereophotogrammetry. 
2. The stereophotogrammetric instruments utilized in this work are based on the principle 
of plotting from aerial photographs under condition of transformation of bundles of 
projecting rays. It is therefore possible to plot on these instruments from photographs 
obtained with aerial cameras of any wide-angleness without replacing projection 
cameras. The problem of spatial intersection in instruments utilizing the principle of 
transformation of bundles of projecting rays is solved quite rigorously; the speed of 
plotting on the said instruments is increased, and the instruments themselves become 
rather simple in design. The instrumental error of plotters now in use in the USSR 
(stereoprojector, stereograph), as determined by grid measurements, is 1:12,000 of 
flying height. 
3. The photogrammetric extension of horizontal and vertical control is effectuated by 
optical-mechanical or analytical means under an obligatory utilization of elements of 
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