ALL 
^ 
   
  
adds Ec ucl t 
   
A 
  
  
  
  
  
  
   
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Before Measurement Measurement (L-R),- Errors in the E 
t N rrors in th lott 
Tes or after + No. 2 AL.-Ry *aver measurements € sortis 
 slotting| L4 M|M-R|L -R| ej |L- MIM9R[|L-R| ep » 2 Ae (Ae)? aver. ^ “syst Ve aver; e yst! 
1 B 2.32 12.35 | 4.67 |- 15 2.32 | 2.32 | 4.64 0 +30 - 8 15 225 +22 484 
2 B 33 35 68 |- 10 34 37 71 |- 15 -30 -13 5 25 +17 289 
3 A 30 37 67 |- 35 29 35 54 |- 30 +30 - 32 5 25 - 2 4 
4 A 28 34 62 |- 30 29 33 62 |- 20 0 - 25 10 100 +5 25 
5 B 29 34 63 |- 25 29 34 63 |- 25 0 - 25 0 0 $$ 25 
6 B 30 34 64 |- 20 30 33 63 |- 15 *10 -18 5 25 *12 144 
7 A 28 37 65 |- 45 27 36 63 |- 45 *10 -45 0 0 - 15 225 
8 B 27 35 62 |-40 30 33 63 |- 15 -10 -27 25 625 + 3 9 
9 B 28 36 64 |- 40 30 36 66 |- 30 - 30 -35 10 100 - 5 25 
10 A 28 38 66 |- 50 30 36 66 |- 30 - 0 -40 20 400 -10 100 
1! A 27 38 65 |- 50 27 33 60 |- 30 *50 - 43 25 625 -13 169 
12 B 28 34 62 |- 30 30 32 62 |- 10 0 - 20 20 400 *10 100 
13 B 28 34 62 |-30 27 37 64 |-50 - 20 - 40 20 400 -10 100 
14 A 28 37 65 |- 45 28 36 64 |- 40 *10 -42 5 25 - 12 144 
15 A 28 33 61 |-25 27 35 61 |-40 0 -33 15 225 - 3 9 
16 B 27 34 61 |-35 30 34 64 |- 20 -30 2:27 15 225 + 3 9 
17 B 31 33 64 |- 10 29 33 62 |-20 *20 - 15 10 100 +15 225 
18 A 26 36 $2 |- 50 26 38 64 |- 60 - 20 - 55 10 100 -25 625 
19 A 26 34 60 |- 40 27 37 64 |-50 -40 -45 10 100 -15 225 
20 B 29 35 64 ,- 30 28 36 64 |- 40 0 - 15 10 100 +15 225 
4.64 + 
Results mm 30 IN + 136 
  
  
  
  
  
  
  
  
  
  
Table 17:2 Checking of the slotter 
Fig. 3. The checking results for the precision slotter used in the author’s experi- 
ments. The templet-material was steel-plates 0,12 mm thick. The mean square 
error in the slotting was 13 u! 
2:0 that the variation of inclination with the length of the radial (R 
in km) follows a simple first-grade empirical formula 
tgd = T (0,016 — 0,0018 R) 
Furtheron the influence of the inclination of the radials can be redu- 
ced 
1:0 through choicing the radial points under stereoscope 
2:0 through using the nadir point when nadir distance is great; 
in the nadir point these inclinations have no influence on the direc- 
tion angles. 
Other errors in the direction angles are caused by the use of paper 
prints, without dimensional stability, by errors in point transference 
and many other small sources of error, all of which have been studied 
in details by the author and found to be possible to reduce or eliminate. 
The use of paperprints must for example be absolutely condemned as 
the differential shrinkage causes errors of the magnitude 16^ or about 
the same as an inclination of 6* when the terrain is slightly broken. 
Point-marking directly in the negatives is recommended and as the 9 
ordinary points in every negative covers only less than 0,003 % of the 
negative area this “damage” cannot be of much harm! The point trans- 
ference can be made with a mean square error of + 0,02—0,03 mm 
according to Dutch investigations. With suitable devices the point 
transference can be done with this high accuracy rather fast. In the 
next stage, the slotting, it is practical possible to reach an accuracy of 
about — 0,01—0,02 mm. 
Summarizing these and here unmentioned other facts it 1s proved that