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(395) 
of high accuracy. The plotting was performed on a stereoplanigraph in Munich 
and thanks to the courtesy of the firm Wild was repeated on an A-5 in 
Heerbrugg for checking purposes, We used the same photographs (flying height 
2000 m, f = 21 cm Aviotar) but we changed the instrument scale in both cases. 
It was 1:10000 and 1:5000. The result was better when using 1:5000. The 
accuracy obtained was proved in the following manner: In each model 5-14 
marked control points were given with very accurate plan coordinates. As only 
2 control points are necessary for fixing the model in plan 3-12 control points 
with 6-24 coordinates are supernumerary. If the model is orientated by help 
of the necessary two control points the supernumerary control points show 
little errors. These errors can be brought to minimum by changing the scale, 
by a little rotation round a vertical axis and by two displacements in the x and y 
direction. This is done by adjustment with the method of least squares. We get 
in this manner for each model the mean errors m for the two coordinates. 
The results obtained are given in the following table: 
  
  
  
  
  
  
  
  
  
Autograph Wild A 5 | Stereoplanigraph C7 
Nr. of model m | control points m | control points 
Instrument-scale 1:5000, flying height h — 2150 m 
2069/70 = 12cm 5 Rn 5 
1989/90 + 17 cm 13 [470712 em 13 
2088/89 + 29 cm 12 = 19 cm 14 
1961/60 — 18 cm 5 
1960/59 zc 12 cm 6 
1959/58 5 cm 8 
1958/57 + 10 cm 3 
1957/56 + 23.cm 5 
Instrument-scale 1:10 000 flying height h = 2150 m 
1961/60 dz-35-cm | 5 | = 29 cm 5 
1960/59 + 26 em | 6 | == 38 cm 5 
1959/58 * 36cm | 8 | = 29 cm 5 
  
Herefrom we have for the instrument-scale 1:5000 a mean error of 
m — 17 cm, in the terrain, this corresponds to a value m, in the image plan 
m.f 170 mm. 210 mm 
meth [356600 
for the image scale 1:10 000 m — 32,0 cm, this corresponds to a value of 
m.f 320 mm. 210 mm 
h 2150 . 1000 
= 0,017 mm, 
= 0,031 mm 
Mo.