ir 
21, 
ts 
  
  
  
  
37 
35 Expressions ‚for “the Accuracy to be. expected. in 
the fin&l--coordinates and elevations, as functions 
of ithe accuracy of “the fundamental ‘operations. 
Introduction. 
For the derivation of the formulas below the following general assumptions 
are made. 
Systematic errors of the fundamental operations are in principle known and 
can be corrected for. The residual errors are assumed to be at least 
approximately normally distributed and to be determined as standard error 
of unit weight S and $0 of image coordinate and y-parallax measurements 
respectively. The basic measurements for the determination of these stan- 
dard errors are in principle assumed to be performed in the actual instru- 
ment with photographs from the actual camera and by the actual operator. 
The number and the location of the control points have also to be taken into 
account. The precision of $0 and $9: expressed as standard error or with 
the aid of confidence intervals, evidently is of basic importance for the 
precision of the standard errors of the coordinates. 
Approximately vertical photographs are assumed. 
Further, distinction must in principle be made between moderate and larger 
elevation differences on the ground. 
3.1 Moderate elevation differences. 
  
3.11 Two control points in planimetry and three in elevation. 
The control points ia planimetry are assumed to be located close to the 
principal points of the photographs and the elevation control points in the 
model points 11, 19 and 95, see fig. 3 in the report. 
Under the assumptions made we find the following expressions for the stan- 
dard error of the coordinates x, y and z of arbitrary model points, expressed 
as functions of the standard errors of unit weight of the fundamental opera- 
  
  
  
  
tions. 
hif. 2[(e2) y^ 4 x"Gew)” | x ce)” 
S: - — 58 4 + & 16 T 4 t 
x € 6b 2b'd bd m 
2 2 2 3 2 à 
L3x (x-b) y 4X (x-b) 4 280" = + 2 2 X +1)