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PRESENTATION OF THE GENERAL REPORT 105 
ISP in London, 1960, and will present the data 
and the results of this experimental work for 
discussion at the meeting to be arranged at the 
Congress for Commission III". On the basis of 
the answers received, none of which objected to 
the general principles of the rules, it appeared 
that the number of probable participants was 
high enough to justify such a burden of work. 
The Commission President, in circular No 3 
sent out in August 1958, announced that he 
would take upon himself the task of organising 
these experimental research works in the same 
spirit and in accordance with the rules enacted. 
In the same circular the President was 
pleased to announce that the French IGN 
director had declared himself willing to allot to 
his institute the heavy task of establishing the 
polygon on French territory and to carry out all 
the necessary measurements to determine con- 
trol points. Furthermore, IGN stated their 
willingness to carry out flights on behalf of other 
organisations against a partial refund of ex- 
penses. The President accepted the generous 
offer with gratitude as well as the proposal to 
establish a polygon in the Massif Central zone. 
As, however, in these requests the flight 
characteristics were in substantial agreement 
with those planned by the IGN own flights, an 
appropriate agreement was soon reached by the 
three centres on the proposal of the IGN 
director himself to effect a single flight with 
three cameras on board the same plane at the 
same time, and with characteristics on the 
average agreeing with the requests, namely, 
height, 8,000 metres; side lap between 15 and 
20 per cent ; three transversal strips. The flight 
expenses were divided by the French Institut 
Géographique and the ETH Photogrammetric 
Institute of Zurich. 
On July 3rd and 4th, 1959, two flights were 
carried out by a B.17 aircraft belonging to the 
IGN group. On it there were a SOM camera 
with statoscope, a Wild camera and a Zeiss 
camera . On July 9th a supplementary flight was 
carried out in order to complete the overlap 
with the Wild camera. The characteristics of the 
flight are stated in the Report. The French IGN 
agreed to bear the expenses of all positive 
reproductions on plates and paper to be distrib- 
uted to the participants together with all data 
concerning the cameras and auxiliary instru- 
ments employed, a list of control points, about 
250, and relative descriptions. The photographic 
materia] obtained through these flights though 
remaining the property of the organisations 
bearing most of the expenses was, however, put 
at the disposal of those intending to take part 
in these trials, against a refund of the mere 
expenses of reproduction. 
The availability of such interesting photo- 
graphic material, the essentially experimental 
aim of these tests and the absolute sense of 
freedom of movement drew the interest of many 
centres on the experimental research of Com- 
mission III. In the autumn of 1959, namely 
when the polygon was completed, the participa- 
tion in Commission III's experimental research 
had grown to the number of seven centres, each 
of which had more or less precisely outlined 
its own aims. Unfortunately, the time left was 
very short and the hope of presenting to the 
London Congress a series of copious results 
diminished from day to day. However, above all 
due to the generous collaboration of the French 
IGN, ever ready to help, the work of sending 
out material went on without interruption over- 
coming sometimes great difficulties and was thus 
completed in the spring of 1960. 
As can be seen by the documentary history 
of the organisation of flights and material dis- 
tribution, and despite the goodwill shown by all 
and by the French IGN in particular, measuring 
work could only be started very late. The 
French IGN had started triangulation work 
about the middle of January, 1960, and from 
that date they sent out periodically, as con- 
templated by the rules, copies of all measure- 
ments, documents and computation results. 
The Canadian centre in its turn had started 
measurement work in the middle of March, and 
this centre likewise kept the President's bureau 
informed of their progress. Since no further 
news was collected the President of Commission 
III invited, by letter dated June 13th 1960, the 
participants in experimental work to send a 
detailed report on the stage reached and on 
the methods of procedures. All participants 
answered within the fixed date replying to all 
our queries. Three of the seven centres partic- 
ipating informed us that they had not yet begun 
the work. The other four, namely, the American 
centre, Mr Brandenberger; the German centre, 
Professor Fórstner; the Canadian centre, Mr 
Schut; and the French centre, Mr Daniel, an- 
nounced that they had already begun the work. 
The two latter sent detailed reports on the stage 
reached and on the first results. All details will 
be found in the published Report. 
  
  
  
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