GeoMax Zoom80 Series - Page 169

Technical Data Zoom80 | 169
Reduction to
mean sea level
D
2
The values for D
2
are always negative and are derived from the following
formula:
Projection distor-
tion D
3
The magnitude of the projection distortion is in accordance with the projection
system used in a particular country, for which official tables are generally avail-
able. The following formula is valid for cylindrical projections such as that of
Gauss-Krüger:
In countries where the scale factor is not unity, this formula cannot be directly
applied.
D
2
Reduction to mean sea level [ppm]
H Height of EDM above sea level [m]
R 6.378 * 10
6
m
TS_106
ΔD
2
= -
H
R
· 10
6
D
3
Projection distortion [ppm]
X Easting, distance from projection zero line
with the scale factor 1 [km]
R 6.378 * 10
6
m
TS_107
ΔD
3
=
X
2
2R
2
· 10
6