Geography Reference
In-Depth Information
From these mapping equations, we derive cha-cha-cha (“change from one chart to another chart”)
tan V
cos U
tan B
cos L ,
tan L =
versus tan U =
(20.7)
tan U
tan L
1+tan 2 V/ cos 2 U
1+tan 2 B/ cos 2 L
tan B =
tan V =
versus
(20.8)
sin U
cos 2 U +tan 2 V
= sin L
=
cos 2 L +tan 2 B ,
in particular, the diffeomorphism
d U
d V
=
=
d L
d B
,
sin L tan B
cos 2 L +tan 2 B
cos L
cos 2 B cos 2 L +sin 2 B
(20.9)
cos L
(cos 2 L +tan 2 B ) 1 / 2
sin L tan B
(cos 2 L +tan 2 B ) 1 / 2
d L
d B
=
= tan V sin U
d U
d V
.
cos U
cos 2 V (cos 2 U +tan 2 V )
cos 2 U +tan 2 V
(20.10)
cos U
(cos 2 U +tan 2 V ) 1 / 2
sin U tan V
(cos 2 U +tan 2 V ) 1 / 2
2
3 IJ
Boxes 20.1 and 20.2 summarize the surface geometry of
, in particular, the
matrices F, G, H, and J of type Frobenius, Gauß, Hesse, and Jacobi as well as the curvature
matrix K :=
E
A 1 ,A 2 ⊂{ R
}
HG 1 , especially the surface fundamental forms
{
I , II , III
}
.
A 1 ,A 2
be a smooth curve which is parameterized by arc length.
Denote by { D 1 , D 2 , D 3 } its Darboux frame defined by ( 20.11 ). Its derivational equations are
given by ( 20.12 ), introducing the antisymmetric connection matrix Ω( κ g n g ) containing geode-
tic curvature κ g , normal curvature κ n ,and geodetic torsion τ g . In terms of the first fundamental
form, in particular {G KL } , the second fundamental form, in particular {H KL } , the Riemann con-
Let C :[0 ,
]
→{ E
,G KL }
nection, in particular the Christoffel symbols M
, the curvature measures of the curve C as
KL
A 1 ,A 2
a submanifold of
{ E
,G KL }
can be represented by Corollary 20.1 .
U k ( S )
D 1 := d X
{
}
= X
∂U K U K = G K U K ,
d S
D 2 :=
( D 3
D 1 )= D 3 ×
D 1 ,
(20.11)
D 3 := G 3 ,
D 1 =+ κ g D 2 + κ n D 3 ,
D 2 =
κ g D 1 + τ g D 3 ,
D 3 =
κ n D 1
τ g D 2 ,
(20.12)
D 1
D 2
D 3
0
κ g κ n
D 1
D 2
D 3
0 κ g κ n
=
, D = Ω D , Ω =
.
κ g 0 τ g
−κ n −τ g 0
κ g 0 τ g
−κ n −τ g 0
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