ra a i 
B) the marked roof corners, classilied in 4 ca- 
tegories according to the compass bearings of the 
mark, and hence as a rule according to the intensity 
of the contrast with the close surroundings of the 
  
  
roof — 
southern corners: m,,(s, n), — 
m, : 
= u (240.4 on (6 
ik 1000? lani: 6 
western corners: m,, (s, n)» — 
m, 
= + | 9 S zs | 7 
E (14 + 0 1000? [um] (7) 
eastern corners: m,,(s, n)s^ 
m. 
= + (18 —0.34——) m 8) 
EK 1000 Lem] 
northern corners: my, (s, n) 
—_ 
4 m 
I 18 —0.2 —= 9 
© em E (19 1000 ) [um] (9) 
on the average: my,(s , n)1.4 
ms 
t 9 —0.2 — 
d 1000 
) [uml (10) 
The values calculated from Eas. (5) and (10) are 
so close to each other that (5) can be substituted 
for (10). 
C) For the unmarked roof corners, classified 
in four categories according to the compass bearings 
of the roof corners and hence according to the in- 
tensity of the contrast with the closest surrounding 
of the roof — 
W 
  
50um 
  
40 
  
30 
  
  
Puy 
20 
  
10 
  
  
  
  
<r ^ + t " 
southern roof corners: m,,(0, n), — 
= + 3000 —— 
(m; 
western roof corners: m,, (0, n)? — 
1 
ym, 
uml. (11) 
= + 2600 
[um] (12) 
eastern rool corners: my,(o, n) — 
1 
= = 2300 [um] (13) 
V ms 
northern rooï corners: m,, (0, n) — 
DI. 
= + 7000 V [um] (14) 
V Ins 
on the average therefore: m,,(o, n) — 
1 
1 
= 3 2500 7 — [nml (15) 
V ms 
Separate graphs for southern, western, eastern 
and northern roof corners represent the above rela- 
tions for the four scales under discussion, in Fig. 5. 
The equations (5) to (15), expressed graphic- 
ally in Fig. 5, prove that the values of the mean 
planimetric errors [in um on the image scale]: 
a) can be considered virtually constant for the 
marked points of the photogrammetric test field (at 
the given scales); 
b) are very close to the values for the marked 
test-field points in the case of marked rooíi corners; 
c) are higher than those for marked roof corn- 
ers and diminish with the image scale in the case ol 
unmarked rool corners. 
   
     
  
  
| € 
ib 
| | | 
| | 
| | 
Li Ll e. À 
Cy Q € e - 
5 € e . 
Nn 9 co e 
e « oN e oe © e © 
v oN - oN