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financial weight and, probably, a scarcely feasible task possessing all the necessary 
seriousness, for the Presidency, owing to the unavoidable difficulties of effectively 
carrying it out throughout the work stages. 
“In June 1958 a Circular (n. 2) was sent out to Rapporteurs, Commission experts 
and all the National Societies belonging to I.S.P. by which the directions given in the 
first rules were clearly modified in the manner said above. 
“The circular recepients were invited to express their opinion, make remarks 
and suggest amendments. 
“The rules enacted are reported herewith: 
“1 - In accordance with the resolutions passed by the VIII Congress of the 
I.S.P. (Stockholm, July 1956), Commission III intends to continue the experimental 
researches that roused great interest during the preceding four years. 
“These works deal with the problems of large blocks of strips, a highly topical 
problem. 
“Owing to the great practical interest of these experiments, consideration must 
be given to the different experimental proceedings and attention must not be limited 
to a comparison of the results simply on the basis of the standard errors in control 
points. The aim of experiments organized by Commission III is to provide a vivid 
and practical documentation of the different methods of carrying out the several ope 
rational steps (flight, plotting and adjustment), for a map requiring a given average 
precision. 
“Thus, these researches exclude anything in the nature of competition. 
“The Commission Ill’s President organizes the work and watches its various 
stages. 
“Persons intending to take part must undertake to supply their results together 
with a detailed description of the methods used and shall follow the rules laid down 
by Commission III. 
“2 - The purpose of these experiments is to determine by aerial triangulation 
the planimetric and altimétrie ground net necessary for plotting on the scale 1:100.000. 
Flights shall be made over a single polygon, the dimensions of which will be about 
80 X 80 km“, on not excessively rough ground. 
“The polygon will be chosen by the Institute that will undertake to carry out 
the ground works in agreement with the Commission III President. 
“Participants may take or may have flight taken with the equipment and in the 
conditions that they consider suitable for the problem to be solved. In particular, 
they are free to choose: 
— the photo scale 
— the photo material 
— the method for taking photographs (arrangement of strips-overlapping) 
— the auxiliary instruments 
“Participants wishing to use special proceedings and instruments must undertake 
to contribute to the cost. They shall, at the time of accepting works, give details of 
flight proceedings and of characteristics of necessary ground points. 
“3 - Polygons will include a certain amount of control and ground points. 
Participants may choose the ground points: the control points will be chosen by 
mutual agreement between the President of Commission III and the Institute taking