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For about ten years now, photogrammetry and data technique have 
been excellent devices when planning roads and hydro-electric power 
plants in Sweden. The good experiences gained from these spheres have 
been applied to other parts of community building. Of special interest is 
the work that has been devoted to the development of digital terrain 
models. During the last two years a few systems of this kind have appear 
ed which have been used with great success in the planning of roads 
and of residential and industrial areas. In this, photogrammetric methods 
play a big part, partly when judging the nature of the ground (geological 
photointerpretation), partly in the gathering of terrain data. 
In order to improve the quality of picture interpretation, both ordinary 
colour film and spectrozonal film have been used during this period. 
As regards mapping within towns and large communities, it may be 
noted that the intense urbanization has been accompanied by an 
increased need of large-scale maps. Thanks, among other things, to the 
improved quality of the film material (estar base), photogrammetric 
mapping in the scales 1:400 and 1:500 has given fully satisfactory 
results for the purpose. 
Production 
The production is mainly engaged in the preparation of official 
maps i. e. topographical maps in the scales 1: 50,000 and 1: 100,000 and 
the economic map in the scales 1: 10,000 and 1:20,000, and in mapping, 
measuring and the production of photogrammetric material for various 
purposes within the process of community building. There is also 
a large production of pictures for forestry purposes. 
The official maps are produced by the Geographical Survey Office, 
which also carries out all aerial photography for measuring and mapping 
purposes within the country. Thus the production of aerial photogram 
metric material takes place centrally and the material is thus accessible 
to all the consumers. The rest of the production takes place within nu 
merous State departments and concerns as well as in private firms. The 
principal producers are listed in Appendix 1. 
The object of the production is mainly to satisfy Swedish demands.