Geoscience Reference
In-Depth Information
Table 6.2 Inverse solution of the Gauss projection: sample computation
Computational results
6
zones
3
zones
Given data (m)
Ellipsoidal parameters
x ﾼ 3,354,874.257
Krassowski Ellipsoid
B ﾼ 30
18
0
46.92
00
B ﾼ 30
18
0
46.92
00
y ﾼ 386.564
L ﾼ 117
00
0
14.47
00
L ﾼ 60
00
0
14.47
00
y
false
ﾼ 20, 500, 386.564 GRS75 Ellipsoid
B ﾼ 30
18
0
48.80
00
B ﾼ 30
18
0
48.80
00
L ﾼ 117
00
0
14.47
00
L ﾼ 60
00
0
14.47
00
GRS80 Ellipsoid
B
ﾼ
30
18
0
48.85
00
B
ﾼ
30
18
0
48.85
00
L
ﾼ
117
00
0
14.47
00
L
ﾼ
60
00
0
14.47
00
x
ﾼ
532 548.378
Krassowski Ellipsoid
B
ﾼ
4
48
0
57.62
00
B
ﾼ
4
48
0
57.62
00
116
59
0
53.21
00
59
59
0
53.21
00
y
ﾼ
209.135
L
ﾼ
L
ﾼ
4
48
0
57.92
00
4
48
0
57.92
00
y
false
ﾼ
20 499 790.865
GRS75 Ellipsoid
B
ﾼ
B
ﾼ
116
59
0
53.21
00
59
59
0
53.21
00
L
ﾼ
L
ﾼ
4
48
0
57.93
00
4
48
0
57.93
00
GRS80 Ellipsoid
B
ﾼ
B
ﾼ
116
59
0
53.21
00
59
59
0
53.21
00
L
ﾼ
L
ﾼ
To carry out computations, we use computer programming based on the methods
and formulae above. The results of the sample computation are shown in Table
6.2
,
(assume that the central meridian in the 6
zone 20 is chosen as the central meridian
in both 6
and 3
zones).
6.4.3 Transformation of Gauss Plane Coordinates Between
Adjacent Zones
The Basics
To constrain distance distortions of the Gauss projection, the area of interest should
be divided into zones along the meridians. The result of such a zone-dividing
projection is that the unified coordinate system on the ellipsoid is divided into
separate plane rectangular coordinate system in each zone. Hence, the points in
adjacent zones belong to two coordinate systems; if transformed into the same
coordinate system, the Gauss coordinates in one zone should be transformed into
the coordinates in the neighboring zone, which is known as the Gauss coordinate
transformation between adjacent zones.
In applications, transformation between adjacent zones is needed on the follow-
ing occasions:
1. When geodetic control networks cross between different projection zones,
coordinates of the adjacent zone should, partially or totally, be transformed
into the same zone before adjustment computations are carried out.
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