The mean flying height is determined through scale measurements on 
control points in the area which are visible in the stereo model. 
A and K are calculated using the elevations of the control points: 
P. H, "P...H P, . Py + (H, - Ha) 
2 = and K = (6) 
P, - P Py - Py 
  
  
The elevation of any point along the planned road can now be 
determined from : 
K 
Hy = 2e = (7) 
i 
The photo scale in road point i is then : 
cC. Tr 
c à 1 (8) 
  
1000 2; 1000 2 K 
The total distance covered in terrestrial meters is computed from : 
: 0 . 
Po-x(a. 199945) (9) 
C . DP, 
i 
Measurements taken on four landmarks visible in the 1 : 10,000 
scale aerial photographs resulted in the following values 
A z 2h69 m. and K - 121150 m.mm. 
The starting point of the new road, which has a stereoscopic 
parallax equal to P, = 91.2 mm, is at a calculated elevation of 
Hy = 1031 m. The photo scale is this point is then 1 : 9587. 
In table 1, columms 7 and 8 the data are given for the elevations 
and scales of the road points. Columm 9 shows the accumulated 
distance covered in the terrain, which amounts to 1041 m. for this 
section. 
A profile along the traverse is constructed by setting out the 
calculated elevations of the road points against the accumulated 
distance from the starting point (see figure 3). 
elevation Tracing AB shortest route, with maximum gradient 8% 
l 
1050 1m. Tracing AB, : longer route, but smallest gradient. 
10491 
1050 | 
10351 
  
10304 
  
  
0 200 400 600 800 1000 1200 1500 m. 
Field distance D