68 
1957 the difference of the weight numbers between the center line and 
the edges of the strip can be expressed by the term 
2dr WM 
p? p 
  
For b — d — 0,6 h this term becomes about 10. 
Adding this term to (273) we find 
1 
Q nin +18 (4€ n° + 39 n? — 31 n + 219) (276) 
The corresponding standard error can be graphically demonstrated. 
Evidently there are only minor differences with the expression (273). 
The expression (273) is graphically demonstrated in diagram 15 for 
Sy = 1: 
3.213. The elevations 
For an investigation of the accuracy of the elevations along the strip 
the same principles can be used as concerning the x- and y-coordinates. 
The expressions (212) and (215) can be substituted into (231) and 
this expression can be developed. We will, however, use another, more 
direct derivation of the differential formula of the elevations as func- 
tions of the elements of the external orientation. 
First we use expression (231) which is applied to the nadir points 
? — 1 and i of the model i — 1,4. We denote the total elevation error 
in the former point by DH, , , ,. and in the latter one by DH, —Lir 
For $;.170 and x, =} 
= 0 y; — 0 we find from (231) 
h? h? + 6 h 
DH, wa == ji Dq i17 b Ds P Dbz, + 5 (DX; { — DX;) EE 
+ dh jyG (277) 
+b h? h ; sin 
DH,;-A07 ^ j Dp, — 5 Doi, — Dbz; , — ) (DX; , DX;) + 
, mo 
+ dh; —1,1) (278)