ACCURACY IN MULTILATED STIRHO-MODELS 
by K A Chlin, cert. engineer, 
Geographical Survey Office of Sweden. 
le Introduction 
In aerial photography for the purpose of stereo-plotting of areas with big surfaces of water, it often is 
necessary to photograph extra photo-strips in order to obtain conventionally workable stereo-models. This 
of course occasions increased expenses, even in plotting. If the coasts are steep and the vegetation dense, 
stereo-plotting is also made more difficult. See [2]. 
In the following we shall 
  
analyse a kind of orien- 
  
tation which is different 
from the traditional. 11 13 15 
See fig l. Relative orien- + + 
tation is assumed to be 91 95 d 
carried out in six points. e 
The points ll, 15, 31 and 
  
55 are fixed with coordi- o O e— middle of > 
nates 0/d, b/d, 0/0 and 31 33 35 photo strip 
b/0. Points 91 and 95's b 
\|/ 
coordinates are designat- 
ed o/e and b/e, where e 
is & variable. 
  
  
  
  
  
The elevation control- 
  
points are assumed to be Fig.1 
situated in points 1l, 15, + point, where y-parallaxes are measured. 
E > 2t 
15, 71, 335 and 75. Points O elevation control point. 
13 and 33 have coordinates 
2/a and 2/o. 
Further it is assumed that the aerial photography is done with a wide-angle camera (picture side: flying 
elevation = 3:2). The pictures are supposed to be strictly vertical, the overlap 60 % and the country 
comparatively flat. The pictures are assumed to be free from systematic errors, 
2. Relative orientation 
2.1. Theoretical derivation 
  
The following correlation exists between the Y-parallaxes in the stereo-model and the corrections for the 
orientation elements for dependent pairs of pictures, cf. [1]: 
2 
X. an EX. à Llu 
+ h dbz, n d ÿ 2 +1 + 5 hd t 5 (1) 
p --dby, - (x-b)d W 
* h 
nN 
€ 
When the Y-parallaxes are measured in the previously mentioned points, the following systems of equations 
are obtained: