ad. the for independent models; and the Centre of Western Germany asking to use a R.M.K. 
15-23 Zeiss camera. : 
As, however, in these requests the other flight characteristics were substantially 
agreeing with those planned by the I.G.N.'s own flights, an appropriate agreement 
was soon reached by the three Centres, on the proposal of the I.G.N. Director himself, 
to effect a single flight with the three cameras on board of the same plane at the same 
time, and with characteristics on the average agreeing with the requests, namely: 
height 8.000 metres, sidelap between 15 and 20%, three transversal strips. 
The flight expenses were divided between the French Institut Géographique Na- 
tional and the E. T. H. Photogrammetric Institute of Zurich. 
On July 3rd and 4th, 1959, two flights have been carried out by a B 17 aircraft 
belonging to the I.G.N. group; on it there were: 
; a SOM camera with statoscope 
veport | > : : 
1960) | a W id camera with statoscope 
Yee | a Zeiss camera 
| On July 9th, a supplementary flight has been carried out in order to complete 
| the overlap with the Wild camera. 
The characteristics of the flight are as follows: 
General "characteristics of the photographs taken with the three cameras 
| Flying altitude: 8.900 m above the sea level 
none | Groung height: included between 300 and 1.700 m 
imber | Average height: 900 m 
Com- | Good metereological conditions 
take Quality of the negative plates: good 
spirit 8 normal strips East-West, which cover totally a surface of 85 x 75 km? 
GN 3 transversal strips North-South 
ML. 
tabli- | Photographs taken with Zeiss camera 
nents | Camera R.M.K. 15-23 N? 21.052 — Pleogon Objective 
Focal — 150 mm - 23 + 23 cm? 
other | Pervola Films 
| 90% longitudinal overlap — 15% transversal overlap 
posal Average scale of the plates: 1 : 53.000 
8 strips East-West of 60-65 plates 
gular 507 plates on the whole 
0 m. 3 strips North-South of 60-65 plates 
S ong | 190 plates on the whole 
MI al- | 
| Photographs taken with S.O.M. camera 
| this Camera N° 33 — Aquilor Objective - Focal — 195 mm - 19 x 19 cm* 
anded Gevaert plates ultra flat 
6095 longitudinal overlap — 15% transversal overlap 
went, Average scale of the plates 1 : 64.000 
with 8 strips East-West of 20-21 plates 
165 plates on the whole 
lights | 3 strips North-South of 20 plates 
effect 59 plates on the whole 
dging | tecording of the statoscopic data 
29