56 
Photogrammetrical point determination of the track surveying 
  
Summary of an invited paper prepared by Dr Ing Kothe, Deutsche 
Bundesbahn, Mainz, W. Germany. 
The photogrammetry is used in the Federal Railways in a large 
scale for the reproduction and revision of the geodetic engi- 
neering plan consisting of railway station and line plans. It 
was disadvantagous that in case of reconstruction at the tracks 
and switches for their reckoning and tracing new dates (track 
points) must be determined locally, requiring a necessary 
accuracy of exposure of - | cm. 
With a series of tests with extreme large photo scales (1:1000, 
1:1800) and an evaluation at the stereo-comparator PSK and analog 
restitution with the plotter Planimat of Zeiss was studied if the 
photo coverage by the use of black and white film and colour film 
can be also employed for the determination of the track points by 
coordinates. 
The calculation by means of a block adjustment (PAT M 43) based on 
a point of minor control which showed an standard error (of position) 
of - 1,6 mm. 
As far the photo scale 1:1000 and an evaluation at the stereo- 
comparator PSK concerns standard error of unit weight (mg) of 6 mm 
and quadratic mean values of the tie points (QMV MP) of 5 mm could 
be obtained by an analysis in the stereo-comparator. 
The results of the planimetric block adjustment show values of 1] mm 
for mg and QMV MP of about 9 mm. 
Concerning the photo scale 1:1800 the results of the restitution at 
the stereo-comparator only reach the required accuracy. 
i 
1 the results are almost identical concerning black and white film 
I1 as colour-film. 
A calculation by a bundle adjustment did not produce any accuracy 
increase. 
An economical employment of the photogrammetry is given in a large 
scale. 
(p 
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