NATIONAL REPORT OF AUSTRIA
by
K. Neumaier.
Since the last congress, photogrammetry has had an ever more and more
expanding development in Austria. Besides a large amount of terrestrial photo-
grammetric surveys, aerial surveys have been carried out in the period of the
report in ever increasing amounts and aerial photogrammetry was applied to
topographical as well as to cadastral and reallocational surveys.
These increased activities were made possible by newly acquired up to date
equipment consisting of 2 Zeiss-Stereoplanigraphs C/5, 1 Wild Autograph A5,
1 Wild Autograph A6, Wild cameras RC5, and Wild RC7 plate camera for
high precision work. Terrestrial photogrammetry is still applied, especially to
complement aerial photogrammetry where sections of the pictures are difficult
to delinaete e.g. shadows of slopes in high mountainous alpine areas, which are
very common in Austria. All in all about 2.800 km 2 , photographed from 640
stations, were surveyed by terrestrial photogrammetry since 1948. On a small
scale terrestrial photogrammetry was applied for hydroelectric power planning,
volume determination surveys and many other technical and construction
purposes.
Aerial photogrammetry was only applied in Austria since 1950 and up till
now more than 3.200 km 2 have been photographed and compiled in maps
1 : 10.000 as the base for the topographic map work 1 : 25.000. To establish the
necessary minor control aerial triangulation has been used with very satis
factory results, both from an economical point of view as well as from the
considerations of accuracy. This in spite of most unfavourable terrain with
average elevation differences of 800—1.000 m in single models.
From 290 models 640 minor control points were determined by this pro
cess using a Zeiss-Stereoplanigraph C/5. For adjustment a graphical method
was applied. Recently the graphic orientation method of Prof. Krames was
applied for our triangulation work resulting in cutting orientation time and in
a propagation of errors more satisfactory for adjustment.
Extensive test surveys for high precision mapping e.g. cadastral surveys
have been carried out to determine the most economical photo scale, which
still gives a satisfactory accuracy. The test programme was extended to areas
with different topography. The conclusion reached was that by the use of a
Wild RC7 plate camera a phototaking scale 1 : 7.000 corresponding to a flight
height above ground of 1.200 m = 3.900 ft was sufficient. Restitution was
made with a Wild Autograph A5 complemented with special compensating
plateholders to compensate for residual distortion. It may be here emphasized
that no special signals were laid out, but the existing boundary markers in the
field e.g. stones with top surface 10—12 cm/square were just chalked white.
The results obtained were more than satisfactory and this process will be
adopted as a standard method for precision cadastral surveys in areas suitable
for that kind of work. Extract of our results can be studied at the Austrian
exhibition stand.