SS 
Applying the general law of error propagation to the expressions (3) 
and (4) the weight numbers of the coordinates x and y can then be 
found. The differentials db are excluded, since the base can be arbitrarily 
chosen before the transformation of the coordinates x and y to the 
ground system. 
1.151. Error distribution after the intersection 
According to HALLERT 1957 a the weight numbers of the coordinates 
x and y can be expressed as follows 
(482402) (+02) (42 — b?)2 (422 +30) (AP —)2F 
Qu = p t 16 61 y? t B® 
  
  
4? (240%) (42 + 0!)(42 +30) SP 
ERIT Ute Ty vr e» 
  
In the expressions (8) and (9) the #-coordinates are referred to a 
coordinate system, the origin of which is located in the middle of the 
h 
base, |x = —]. In the derivation the following substitutions were also 
9 e 
used 
a v y y 
b D bio iu 
The standard errors of the coordinates x and y are then obtained as 
m, — $8 LA (10) 
m, m$ } Q M ( 11 ) 
where s, is the standard error of the image coordinate measurements. 
The expressions (10)—(11) are graphically demonstrated for s, — 1 in 
diagrams 1 and 2. In these diagrams the error distribution is demonstrated 
within the image pair with respect to the intersection procedure only. 
When the intersected points are to be transformed into the coordinate 
system of the ground at least two control points have to be used for 
the coordinate transformation. It is of particular interest to investigate 
the error distribution after such a transformation. Evidently the co- 
ordinate transformation means that a certain compensating effect in 
the control points has to be taken into account. This will be made clear 
from the following discussions. 
  
  
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