Zeller treated D and ¢ as uncorrelated parameters. 
m "m 
equations read as follows: 
  
: 2 2 
= t Vm, si On) + (m cosy) 3 
  
22 2 
£n, sina) + (m 6056.) , and 
  
2 e 
se, + (m sing) : 
Even though the results obtained by our equation (10, 11, 
and 12) did not show substantial increase in accuracy to warrant 
the replacement of Zeller's equations (18, 19, and 20), we did 
use our equations in the error analysis for the sake of statis- 
tical perfection. 
In case of convergent photography, equation 10, 11, and 
12 were used after properly deducing the angle Qa In such 
cases, the camera coordinate system was redefined as having 
its x-y plane formed by the x-axis of the left plate and the 
left chamber optical axis. 
In case of this oblique photography, equation 10, 11, 
and 12 obviously are referred to an inclined coordinate system 
(X,Y; and Z in Fig, 24). The values for m y ny 
were determined through the well known ''pedal curve'' as 
follows (Jordan-Eggert, 1948) : 
^ and m.