5 
the ground measurements, with the most uniform distribution over the whole block’s 
surface. 
4 '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. Partici 
pants who have not carried out the flight operations themselves, shall advise 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. 
“5 - At the end of the work, each organization, taking part in it, shall send the 
President of Commission III a detailed report on the work done, containing: 
— the description of the plotting method used 
— a table showing work times for each stage 
— a description of the adjustment methods used 
— a table containing: 
the adjusted coordinates 
the discrepancies in the adjusted coordinates of each point 
— any further information concerning the work done. 
“In its turn, Commission III shall publish all the reports in the General Report 
that the Commission will submit to the IX Congress of the I.S.P. in London (1960) 
and will open the data and results of this experimental work to discussion at the meet 
ing to be arranged at the Congress, for Commission III. 
“On the basis of answers received to questions contained in Circular n° 2 and 
none of which objected to the enacted rules’ general principle, showing that the number 
of probable participants was high enough to justify such a burdensome work, the 
Commission President in Circular n° 3, given out in August 1958, announced to take 
on himself the task of organizing these experimental research works in the same spirit 
and in accordance with the rules enacted and accepted. 
“In the same circular the President was pleased to announce that the French 
I.G.N. Director had declared to be willing to allot to his Institute the heavy task of 
establishing the polygon on French territory and to carry out all the necessary mea 
surements to determine control-points. 
“Furthermore, I.G.N. stated to be willing to carry out flights on behalf of other 
Organizations, against a partial refund of expenses. 
“The President accepted this generous offer with gratitude, as well as the pro 
posal of establishing a polygon in the “Massif Central” zone. 
“It is an area of 80 x 80 knr in the high valley of Loire and Allier, in very 
irregular regions whose average altitude is 800 m, with heights between 340 and 1.600 m.