-11- 
j-L] is the mean square error due to identification of the point 
p in the terrain as well as on the photography during 
plotting, 
f^-ppLs the mean square error due to the deformation of the 
bundle of rays and due to the operator, 
is the mean square error due to drafting work, 
f i is the accuracy (mean square error) in determining the 
”gc 
ground control (in planimetry)j 
ptj_l is the accuracy (mean square error) in determining the 
CjC 
ground control (in elevation)> 
nrip is the mean square value of the error in planimetry due to 
the combined effect of all sources with the exception of 
Ground Control, Aerotriangulation and its adjustment 
(H-Pgc & M- p^), 
rrip| is the mean square value of the error in elevation due to 
the effect of all sources with the exception of Ground 
Control, Aerotriangulation and its adjustment (/^_j c & M'Hf ^ 
3 t/\ 
and m yp is the mean square error in measuring parallax (in image plane), 
then, the following relation could he given: 
or 
fXj - flp tn + M'cdS + Md + Mpp +• M'd + Mp ( 3 ) 
fly = M'D 
tv 
2 2. 
[Dp + M"D 
pc 
(k) 
The values of such factors depend, of course, on the photogrammetric 
system used. In the case of a reasonably reliable operator and a stereo 
scopic instrument of precision comparable to that of the Wild A8