Sweden 6 
Table 7 
Data of the Planes. 
Type of plane 
Maximum 
altitude 
m 
Cruising 
speed 
km/h 
Maximum length 
of flight 
lb 
Focke Wulff ’’Weihe” 
4 500 
200 
4 1/2 
NC 701 Siebel 
7 000 
270 
6 
B 3 (Ju 86) 
7000 
330 
4 — 6 
The ordinary photographs for the Office are generally taken from 
the 4 000 m level and are covering parallel strips, usually running N-S. 
When the ground is flat the relative distance between the lines of 
flights is as a rule 3.5 km, which means a lateral overlap of about 40 %. 
Exposures are timed so as to ensure a longitudinal overlap of about 
60 %. If the altitude differences in the area to be covered are appre 
ciable, photographs are also taken along intermediate lines of flight. 
Photographs to order are taken at varying heights and overlaps accord 
ing to their intended use. The camera equipment now used by the 
Geographical Survey Office consists of a) four cameras of the Zeiss 
RMK or Rb 20/30 30 type bought in or before 1947, and b) three ca 
meras of the Wild RC 5 a type bought in 1952—54. These latter have 
interchangeable camera bodies fitted with Aviogon and Aviotar lenses, 
giving picture sizes of 18 X 18 cm or 23 X 23 cm. 
As the relative aperture of the new cameras is greater than that of 
the older, photographing in cloudy weather is usual. The resultant pic 
tures are free from shadows and excellent for stereo-work. 
For the adaptation of the photogrammetric material the Geographical 
Survey Office disposes of the following equipment. 
Photographic equipment 
4 developing apparatuses 
2 drying drums 
2 contact printers 
1 pneumatic copying apparatus 
1 reproducing camera 
4 reducing equipments 
4 rectifiers 
Stereoscopic instruments 
1 Wild Autograph A 5 
4 Wild Autographs A 6 
1 Wild Autograph A 7 
1 Wild Autograph A 8 
1 Zeiss Stereoplanigraph 
11 Zeiss Multiplex Aeroprojectors