2 
didate of technical sciences G. P. Zukov, who proposed a new definition of the model as being 
the geometric locus of intersection points of rays, plotted from one aerial photograph with 
the corresponding planes of a cluster of planes plotted from the other aerial photograph. 
The creation of universal instruments intended for utilization of transformed ray- 
bundles is considered in the U.S.S.R. as a great achievement on the way to a further 
development of photogrammetric engineering. 
Investigations carried out with regard to utilization of the principle of transformed 
bundles of rays have brought out that, when making a resection with rays the directions of 
which have been transformed, a normal model free of vertical parallaxes may be obtained 
by changing the orientation elements of the aerial picture, namely, the inclination angles 
a, o, and the value of the contour interval h of the model. Then the new values of the 
orientation elements are ka, kw, kb, where k the ratio of transformation F/f,, F being 
the focal length of the stereoplotter projection camera lens, and f, — the focal length of the 
aerial camera. 1) 
The theory described above has not found application in stereoplotters designed for 
making resection in space with the aid of mechanical means. Nevertheless, the theory of 
ray-bundles transformation has 
proved to be very efficient when 
applied to stereophotogrammetric 
instruments intended for making 
resection of the plane, — namely, 
in stereometers. 
The theory of ray-bundles 
transformation permits to easily 
adapt topographic stereometers 
of a focal length 100 mm for 
treating photographs obtained 
with the aid of aerial camera 
lenses of focal lengths 200, 
100, 70, 54 mm, and in this form 
such instruments have found ap- 
plication for mapping at the 
scales 1 : 50,000 — 1 : 20,000 in 
flat and hilly regions. 
In connection with the begin- 
ning of large-scale mapping 
work also in semi-mountain and 
mountain regions, it has been 
found necessary to develop first- 
class universal instruments based 
upon the principle of ray-bundles 
  
transformation. 
Fig. 1. 
The theory of modified re- 
section was adapted by the can- 
didate of technical sciences G. P. Zukov for operating the stereoplanigraph. With this 
purpose in view, the stereoplanigraph was provided with two film carriers, with the aid of 
which the photographs can be displaced from their initial positions onto the so-called 
“decentrations Ax and Ay of aerial photographs”. 
1) See M. D. Konshin, Stereophotogrammetric Plotting with the Aid of Ray-bundles 
Transformation. Proceedings of the Central Scientific Research Institute of Geodesy, 
Aerial Surveying and Cartography, 1944.