Sweden 2 
maps by photogrammetric methods. The Office also performs all pho 
tographic adaptation of the photographs, i. e. produces contact prints, 
rectified and enlarged pictures, diapositives, etc. 
A photo-map of Sweden on a scale of 1:10 000 is prepared as the 
basis on which all official maps are produced. From ! this are after 
wards produced the Economic Map on a scale of 1:10 000, the Military 
Map on a scale of 1:20 000 and — directly or via the> Economic Map -— 
the Topographic Map on a scale of 1:50 000. This last is of a new type, 
the first sheet of which appeared in 1954 (see [54] and [64]). Copies 
of the Economic and Topographic Maps are annexed. 
The Geographical Survey Office will make photographic and line 
maps to order on various scales and for various purposes. The most 
usual are: 
maps for technical purposes, e. g. road and hydro-electric engineering 
work and town planning; generally contoured line maps on scales from 
1:500 to 1:20 000, and 
maps for forestry purposes; photographic and line maps on scales 
from 1:10 000 to 1:20 000. 
These maps are produced on the basis of photogrammetric triangula 
tion. Their detailed contents are obtained by indoor photo-interpretation 
or by field reconnaissances. 
The Extent of the Photogrammetric Activities of the Geographical 
Survey Office. This is accounted for in the following Tables. 
Table 1 
The Number of Recorded Photographs. 
Number of 
Itoutine 
work 
Spec, ordered work 
Total 
Y ear 
aircrafts 
Flying altitude 
Spec. 
In all 
used 
« 4000 m 
< 4000 m 
work 
1952 
3 1/2 
3 449 
1 367 
3 394 
4 761 
8 210 
1953 
4 
3 727 
2 648 
2 100 
4 748 
8 475 
1954 
5 
9 506 
3 030 
5 054 
8 084 
17 590 
1955 
5 
11 908 
4 217 
6 598 
10 815 
22 723 
Total 
28 590 
11 262 
17 146 
28 408 
56 998 
As may be seen in Table 1, the number of photographs taken has 
increased a good deal in the last couple of years. This is due to the 
increasing popularity of photogrammetric methods, as their scope has 
been widened, and the consequent increase in the orders for photogra 
phic aerial survey. The larger number of orders has made it possible 
to use optimum weather conditions more intensively and the equipment 
more rationally.