From the analysis it is evident that the flying altitude and the photo 
material have not affected the plotting result as regards position and 
elevation. There is a certain difference, however, in the contour lines, 
the colour film giving a slightly poorer result than the panchromatic 
material. 
As regards the standard errors obtained, it can be stated that the de- 
mands on accuracy set for the Huddinge mapping were satisfied by all 
the models tested. 
The choice of flying altitude and photographic material can thus be 
made from other premises than the demand for geometric quality. The 
economic points of view seem to carry most weight: to choose the sur- 
veying technique, the flying altitude and the kind of film so that a mi- 
nimum of field work is demanded, which in our opinion suggest a pho: 
togrammetric triangulation to determine horizontal control points and a 
flying altitude of 600 metres using colour film. 
References 
Hallert, B., 1956: Über die Genauigkeit der Luftphotogrammetri. KTH handl. nr. 
194, 1956. 
——— 1964: Glossary of some terms and expressions used in the theory of errors 
of photogrammetry. 
Morén, A., 1967: The geometrical quality of aerial photographs. Inst. f. fotogram 
metri. KTH, Stockholm 70. 
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