dass INTERNATIONAL CONGRESS OF PHOTOGRAMMETRY 1952 
atten 
The photogrammetric production of maps and plans in Switzerland. 
| mit 
fung Report to Commission IV of ICP 1952 
ions- 
Bild. by H. Harry, Berne, Switzerland. 
As can be gathered from the very full replies to the questions of the President 
mes of the Commission, photogrammetry is being applied intensively in Switzerland 
| ge for the production of maps 1 : 25000 and 1 : 50000 and of plans 1 : 10000 up to 
der 1 : 500. As Switzerland is, economically speaking, an intensively organized and 
i rk cultivated country, photogrammetry is here no longer a means for interior coloni- 
soeur zation, for cultivation or the layout of traffic arteries as it is the case in many 
other countries. The value of photogrammetry has nevertheless obtained a large 
economic importance as by this method it was possible to reduce surveying costs 
B er. for map making, for the production of a legal cadaster, to keep up to date official 
ua re maps and plans, to produce maps and plans for manifold purposes, to substantially 
Asa reduce the production times and to improve the quality of the various processes 
accen such as topography in mountainous districts. The centre of gravity lies in high 
precision photogrammetry for large scales. Terrestrial photogrammetry is now 
yor only applied for large scale plans in narrow mountain valleys whilst in all other 
LR cases air photogrammetry is resorted to. Rectification (one-image-photogrammetry) 
| abi is but rarely used in Switzerland as there are no large and flat tracts of land. The 
enk- typical Swiss method is Stereoscopic Photogrammetry with independent pairs of 
kung air photographs, corresponding to the dense geodetic net of our country (1 to 4 
nang trigonometric points per km?). In Switzerland the method using connection of 
htige successive photographs (air traversing) is only of economic value where terrestrial 
surveys of ground points become too expensive on account of terrain difficulties 
yon (inaccessible mountains, large woods). 
ope. Users of maps and plans are increasingly consulting for their work not only 
aren the plans with conventional signs but also air photographs. The existing air 
re material is widely used as interpretation for multitudinous scientific and technical 
emes purposes, in most cases in conjunction with plotting of the photos. In the combined 
use of the plan with conventional signs and air photographs which are the two 
mutually complementary means of representing the earth’s surface, we find new 
and productive possibilities. 
By increasing precision, and thus also economy, important practical improve- 
ments are still possible in the production of maps and plans. Of capital importance 
in this connection is the further increase of the angular precision of the bundle of 
stereoscopic rays as registered with the cameras and reconstituted with the plotting 
machines. The following improvements have been obtained in Switzerland in this 
connection: 
a) the new Wild objectives Aviotar (60° angular field) and Aviogon (90° angular 
field) brought along an important reduction of distortion error and thus a 
substantial improvement of the resolving power and also an improvement of 
the illumination at the edges of the photographs. The definition of the image 
is so good that the remaining distortions can be successfully compensated with 
optical correcting plates in the plotting machines;