1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
|
/*
** libproj -- library of cartographic projections
**
** Copyright (c) 2003 Gerald I. Evenden
*/
/*
** Permission is hereby granted, free of charge, to any person obtaining
** a copy of this software and associated documentation files (the
** "Software"), to deal in the Software without restriction, including
** without limitation the rights to use, copy, modify, merge, publish,
** distribute, sublicense, and/or sell copies of the Software, and to
** permit persons to whom the Software is furnished to do so, subject to
** the following conditions:
**
** The above copyright notice and this permission notice shall be
** included in all copies or substantial portions of the Software.
**
** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
** EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
** MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
** IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
** CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
** SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#define PJ_LIB__
#include <errno.h>
#include <projects.h>
struct pj_opaque {
double phic0;
double cosc0, sinc0;
double R2;
void *en;
};
PROJ_HEAD(sterea, "Oblique Stereographic Alternative") "\n\tAzimuthal, Sph&Ell";
# define DEL_TOL 1.e-14
# define MAX_ITER 10
static XY e_forward (LP lp, PJ *P) { /* Ellipsoidal, forward */
XY xy = {0.0,0.0};
struct pj_opaque *Q = P->opaque;
double cosc, sinc, cosl, k;
lp = pj_gauss(P->ctx, lp, Q->en);
sinc = sin(lp.phi);
cosc = cos(lp.phi);
cosl = cos(lp.lam);
k = P->k0 * Q->R2 / (1. + Q->sinc0 * sinc + Q->cosc0 * cosc * cosl);
xy.x = k * cosc * sin(lp.lam);
xy.y = k * (Q->cosc0 * sinc - Q->sinc0 * cosc * cosl);
return xy;
}
static LP e_inverse (XY xy, PJ *P) { /* Ellipsoidal, inverse */
LP lp = {0.0,0.0};
struct pj_opaque *Q = P->opaque;
double rho, c, sinc, cosc;
xy.x /= P->k0;
xy.y /= P->k0;
if ( (rho = hypot (xy.x, xy.y)) != 0.0 ) {
c = 2. * atan2 (rho, Q->R2);
sinc = sin (c);
cosc = cos (c);
lp.phi = asin (cosc * Q->sinc0 + xy.y * sinc * Q->cosc0 / rho);
lp.lam = atan2 (xy.x * sinc, rho * Q->cosc0 * cosc - xy.y * Q->sinc0 * sinc);
} else {
lp.phi = Q->phic0;
lp.lam = 0.;
}
return pj_inv_gauss(P->ctx, lp, Q->en);
}
static void *destructor (PJ *P, int errlev) {
if (0==P)
return 0;
if (0==P->opaque)
return pj_default_destructor (P, errlev);
pj_dealloc (P->opaque->en);
return pj_default_destructor (P, errlev);
}
PJ *PROJECTION(sterea) {
double R;
struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
if (0==Q)
return pj_default_destructor (P, ENOMEM);
P->opaque = Q;
Q->en = pj_gauss_ini(P->e, P->phi0, &(Q->phic0), &R);
if (0==Q->en)
return pj_default_destructor (P, ENOMEM);
Q->sinc0 = sin (Q->phic0);
Q->cosc0 = cos (Q->phic0);
Q->R2 = 2. * R;
P->inv = e_inverse;
P->fwd = e_forward;
P->destructor = destructor;
return P;
}
|
