funda- 
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gation 
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during 
 Brus- 
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lerable 
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ments 
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and all 
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ust be 
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'ontrol 
  
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 opera- 
tional 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 III'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 altimetric ground net necessary for plotting on the scale 1 : 100.000 
(standard planimetric error 4- 15 m; standard altimetrie error -- 5 m). 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, not exceeding 200, 
will be chosen by mutual agreement between the President of Commission III and the 
Institute taking the ground measurements, with the most uniform distribution over 
the whole block's surface. 
The ground operation will be carried out with sufficient precision for the purpose. 
Each participant in the work will receive sufficient documentation to recognize 
the control points at the plotting stage. The coordinates of the control points will be 
published by the President of Commission III, at a date to be fixed in agreement 
with those participating in the experiments. 
4. — The plotting of work shall begin within two months of the flight. 
Participants who have not carried out the flight operations themselves, shall ad- 
vise the date on which the plotting operations will begin and Commission III will let 
them have the necessary plates. 
Furthermore, every two months, participants shall send the President of Com- 
mission III a description of the work accomplished, and a photographic copy of the 
plotting sheets containing the orientation elements of each model and instrumental 
coordinates for control points. 
Also all participants shall send the President of the Commission a copy of the 
analytic and adjustment operations of the strips' results. 
27