11 
Aerial photography 
The production of these map series is based on vertical 
photography for photogrammetric determination of control 
points and stereocompilation. 
Nominal scale of photography for the topographical map, 
1/50 000, is 1/35 000—1/40 000, and for the large scale map 
1/5 000, the photography scale is 1/30 000, for determination 
of control points, and 1/15 000 for stereocompilation. 
The aerial camera used is Wild RC8, £=15,3 cm and size 
23 X 23 cm. For the large scale map series Wild Aviotar is 
exeptionally used f=21 cm (only some special cases). 
Mapping procedure 
Signalizing of trigonometric points are generally done prior 
to photography, and especially in areas where large scale map 
ping is to be done. The marks are identified on the photos 
for determination of photogrammetric control points and 
used in aerial bridging. 
Together with the determination of photogrammetric con 
trol points on photos on scale 1/30 000, control points for the 
photos, scale 1/15 000, are also fixed for stereocompilation of 
the economic map. 
By stereotriangulation electric coordinate printers are 
used, and numerical adjustment done, strip — or block adjust 
ment, by electronic computer. 
In areas where small and medium scale have to be done 
at the same time, the work on these two map series are co 
ordinated. Only one photography on scale 1/30 000—1/35 000 
is carried out and corresponding common determination of 
control points. 
The photographic material used is original negatives and 
diaposotiv films. 
Stereocompilation is carried out on first and second order 
plotting instruments. The compilation of the medium scale 
maps is based on some field work on the photos beforehand. 
The boundaries are signalized before photography, and after 
wards identified on the photos. Soil classification is also done 
on the photos in the field. These field works are done by 
The Minestry of Agriculture. The compilation of the topo