We feel that a conclusion can be reached, even from the results of these 'short experiments: 
the AP/C, at least in its function of an aerial triangulator, is perfectly comparable with a precision 
plotter as far as its use and, in particular, its accuracy. 
We are grateful to Mr. Colla and Mr. Vanossi for their industrious and intelligent collabo 
ration in the execution of the measures, which has greatly contributed in the good results 
of the work. We also thank Mr. Foland who gave us precious information on the AP/C 
performances. 
BIBLIOGRAPHY 
U. V. Helava, New principle for photogrammetric plotters. O.M.I., Roma. 
U. V. Helava, Analytical plotter in photogrammetric production line. O.M.I., Roma. 
U. V. Helava, Mathematical methods in the design of photogrammetric plotters. Photogrammetria XVI, 
1959-1960, No. 2. 
U. V. Helava, Analytical Plotter using incremental computer. Photogrammetric Engineering, June i960. 
U. V. Helava, An ultimate solution of relative orientation. O.M.I., Roma. 
E. C. Johnson, Systems design of a digital control computer for an Analytical Stereoplotter. Presented at 
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