Geography Reference
In-Depth Information
8
Ellipsoid-of-Revolution to Tangential Plane
Mapping the ellipsoid-of-revolution to a tangential plane. Azimuthal projections in the nor-
mal aspect (polar aspect): equidistant, conformal, equiareal, and perspective mapping.
A 1 ,A 2 :seeBox 8.1 .As
before, F (with elements a, b, c, d )istheFrobeniusmatrix,G=J J (with elements e, f, g )isthe
Gauss matrix, H = [ X KL |G 3 ] (with elements l, m, n ) is the Hesse matrix, J = [ ∂X J /∂U K ]is
the Jacobi matrix, and K = HG 1 is the curvature matrix, finally leading to the mean curvature
h =
First and foremost, let us consider the ID card of the ellipsoid-of-revolution E
tr[K] / 2 and to the Gaussian curvature k = det[K].
2
A 1 ,A 2
Box 8.1 (ID card of the ellipsoid-of-revolution
E
).
Surface normal ellipsoidal coordinates(1st chart: Λ, Φ ):
2 /
3
( X 2 + Y 2 ) /A 1 + Z 2 /A 2
{
Λ, Φ
}∈ E
{
Z =
±
A 2
}
:=
{
X
R
|
=1 ,A 1 >A 2 ,Z
=
±
A 2
}
,
X := E 1 A 1 cos Φ cos Λ
+ E 2 A 1 cos Φ sin Λ
+ E 3 A 1 (1 E 2 )sin Φ
1
1
1
,
(8.1)
E 2 sin 2 Φ
E 2 sin 2 Φ
E 2 sin 2 Φ
X + 180
2 sgn Y sgn X +1 ,
Λ ( X ) = arctan Y
1
2 sgn Y
1
1
Z
X 2 + Y 2 .
Φ ( X ) = arctan
1
E 2
Matrices F , G , H , J , K , andI (elements a, b, c, d ; e. f, g ; l, m, n ):
1 E 2 sin 2 Φ
A 1 cos Φ
=
=
1
G 11
0
1
0
N cos Φ 0
0
F=
1
G 22
1
M
0
E 2 sin 2 Φ ) 3 / 2
A 1 (1 −E 2 )
(1
0
= ab
2 × 2 ,
R
(8.2)
cd
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