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(b; S Charme 0 € 
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(479) 
by experience. It shall be the duty of the General Assembly to so organize the 
work of the Commissions as to facilitate this distinction. 
B. With respect to experimental surveys: 
1. That the experimental aerotriangulation activities intended for the 
establishment of large-scale maps be carried out in accordance with the recom- 
mendations to the Paris meeting (December, 1950) and repeated on page 5 of 
the General Report of Commission II] to the Congress of Washington. For 
aerotriangulation work which is to sérve in the establishment of small and 
medium-scale maps, use will eventually be made of strips of more than 100 kms 
and photographic scales smaller than 1/40.000. 
2. That the international exchange of photographic material and of the 
topographic data necessary for the comparative trials carried out in different 
countries be freed from the hindrances and restrictions now existing. 
3. That the International Society support the organizational efforts which 
tend towards this result. 
C. With respect to subjects for study: 
1. That the comparison between plate and film be studied, not only by 
laboratory tests, but by the results of experimental triangulation activities 
carried out by means of these two emulsion supports, all other conditions 
remaining as similar as possible. 
2. That the nature of the errors be brought out by the study of experi- 
mental strips conforming to the recommendations set forth above. The study 
of each variation of an operational method should be based upon at least three 
plottings carried out in identical conditions. 
3. That improvements in the results be sought through every practicable 
instrumental, operational, and mathematical method, but that the published 
improvements be confirmed by practical applications sufficiently extensive that 
they may be accorded a statistical value. 
36