(488) 
Zeiss-Multiplex (type 1935) from photographs taken with f — 200 mm a height 
of h— 2000 m. For checking we use contour lines constructed with a stereoplani- 
graph from the same photographs. 
If we superimpose the two contour plans (see fig. 1), the same contour lines 
of either plan do not coincide, there are differences between them. The differences 
m; are chiefly caused by the less accurate multiplex-countour lines. We do not 
commit any noticeable error, if we 
Planigraph -Mulfip/ex assume at first the planigraph contour 
Ponga EEE ccr lines to be exact. (As the error of the 
//fbrences m, ; : . : 
old Zeiss-multiplex is about three times 
larger than of the planigraph, the 
weight of the stereoplanigraph lines is 
9 times larger than that of the multi- 
plex-lines). If we measure on 200 pla- 
ces the differences m1 (fig. 1), we 
would have 200 equations of the kind 
(la): 
mi — b + a tg y. 
in each of them the values m1 and y 
are known, the latter can be easily 
taken from the stereoplanigraph-con- 
tour plan. In these 200 equations we 
have only the two unknowns a and b. 
They would be evaluated by a simple 
adjustment. But in order to abbreviate 
this adjustment we order the measured 
values m; into groups according certain 
values of y: O— 3°, 3° — 6° and so 
Fig. 1 on. We take the medium values of mi 
and y in each group. In this way we 
have only a few equations (la), thus the adjustment can be performed very 
quickly. In our case we reached for the multiplex-contour plan the adjusted 
values a = 1,35 m . b — 0,70 m and the equations for m; and my. 
(4) im = 00m 191,5 ce v.m mu — 1,35 + 0,70 tg y. m.. From (3) 
we get with h — 2000 m the accuracy of the planigraph contour lines. 
(5) m; — 0,3 m + 0,4 ctg y m and m, — 0,4, + 0,3 tg y m. 
As the angle y amounts in our case only to 15? and therefore tg y is small 
and ctg y is large we can calculate further on with the simple equations: 
  
  
  
  
for the Multiplex: m. —1,355m-—a mi —1,35mcetgy 
for the Planigraph: mí —0,40m-a mi; =040mectgy. 
Fig. 1 shows the two contour plans superimposed, we see the errors, they 
are caused chiefly by the multiplex contour lines. 
The area shown by the contour lines is quite simple: on the left is a slope 
with some irregularities, in the middle a soft trough, on the right a steeper 
slope caused by a rock bank in the underground. 
It is of interest to compare the two separate contour plans by view. 
Fig. 2a shows the planigraph contour, fig. 2b the multiplex, the contour 
interval is in both cases Ah = 10 m.