85 
  
  
   
  
  
           
  
  
A mZ +m? 
y n-50 
150 + 
100 4 
50 4 
Ti- 5 
0 T T T T T T T > 
n T n Ti 2n 3n Zn n 
8 4 3 2 3 4 8 
Diagram 19. Numerical stereo-radial triangulation. Radial standard errors. Bridging. 
h 
$y — = 1 
c 
The standard error of the elevations is then found as 
(350) 
Wp = So V@r, Rg 
where s, is the standard error of the y-parallax measurements. 
The expression (350) is graphically demonstrated for s, — 1 in the 
diagram 18.