24
The following errors can be derived from the four available photomaps: The
errors of tapping-off in the Coordinatograph (only the accidental portions), the effects
of altimetric errors during scanning, and the absolute errors, which appeared from all
the above-mentioned sources of errors taken together. For the computation of errors
the absolute errors have been subdivided into two groups. The first group involves
those points, which are situated in the middle of the profile strips within an area
extending to a quarter of the strip width on both sides of the mid-line. The second
group comprises those points which are situated in the two exterior quarters of the
profile strips. The following errors have been found (coordinate-errors of x, y and the
mean) :
Tapping-off errors (mean square errors of the means of the tapped-off values in the
photomaps 1 : 3,000)
Map
n
m x
[mm]
m y
[mmj
m c
[mm]
1
63
0.011
0.015
0.013
2
67
0.017
0.021
0.019
3
56
0.013
0.025
0.020
4
68
0.014
0.018
0.016
1—4
254
0.014
0.020
0.017 mm on the map
4
6
5 cm in nature
These tapping-off errors have been obtained from the differences between two measure
ments. Therefore they do not involve irregular errors of the spindle or guide of the
Coordinatograph.
Absolute mean square errors after affine adjustment with all points
Group 1
Group 2
Group 1 and 2
Map
m x
m y
m c
m x
m y
m c
m x
m y
m c
Tl
[cm]
[cm]
[cm]
[cm]
[cm]
[cm]
[cm]
[cm]
[cm]
1
27
28
45
37
36
33
39
36
63
31
41
36
2
30
24
34
29
37
41
51
46
67
35
44
40
3
29
25
37
31
27
33
40
37
56
29
39
34
4
36
29
31
30
32
35
48
42
68
32
40
36
1—4
122
27
37
32
132
36
45
41
254
32
41
37
0.11
0.14
0.12
The above-listed absolute errors in the respective columns have a good conformity with
each other. In general m x is smaller than m y (by about 30%). The mean square errors
of Group 1 are smaller than those of Group 2, as has been expected. If the residual
errors were caused only by errors due to the system, then the mean square errors of
