+ 10 À 
— /0 À 
— 20 4 
  
— 30 - 
ar. 
; A 
+60 
+40 - 
+ 20 
— 20 
— 404 
— 60 4 
  
-— 80 
40 
Computed total "distortion" 
Influence of the earth curvature and refraction 
Influence of the curvature of the pressure plate 
Resulting distortion curve 
  
Fig. 10. The result of an empirical determination of the distortion of Aviogon 6” F: 5,6 wide 
angle lens. Altitude about 4,500 meters. The scale of ice pictures 1: 30,000 
rem 
Fig. 11. The result of an empirical determination of the distortion of Ross’ 6” F:6,3 wide 
angle survey lens. The curve shows the sum of the distortion curve delivered by Williamson C, 
Ltd and the curve from fig. 9 referable to 8,000 m altitude. The dots are the distortion value 
dr,—dr, computed from height observations in an ice model (Altitude about 8,000 meters). 
  
   
    
  
    
   
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
   
    
   
    
     
    
  
  
  
  
  
  
  
  
  
   
    
stereo-plotters a 
of the altitude Î 
which had been 
Since a large 
cerned before th 
the camera mak: 
The distortion c 
used as standard 
ments of these c 
ments of ice ma 
to + 0.05 per m 
The method d 
of an aerial phot 
the practical ph 
ditions. Precisely 
before the begin 
ices in Central S 
also to be an ad^ 
same methods a: 
plotting. It is fr 
flying altitude ar 
ice model measui 
model with or w 
It can perhaps 
result in a refrac 
probably affect or 
of minor importa 
REFERENCES 
1. Leijonhufvud, A.: 
allmánna kartverl 
2. Tham, P.: Lens I 
1946. 
3. Haller, B.: Über 
für Vermessungsw