/src/proj/src/projections/sterea.cpp
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1 | | /* |
2 | | ** libproj -- library of cartographic projections |
3 | | ** |
4 | | ** Copyright (c) 2003 Gerald I. Evenden |
5 | | */ |
6 | | /* |
7 | | ** Permission is hereby granted, free of charge, to any person obtaining |
8 | | ** a copy of this software and associated documentation files (the |
9 | | ** "Software"), to deal in the Software without restriction, including |
10 | | ** without limitation the rights to use, copy, modify, merge, publish, |
11 | | ** distribute, sublicense, and/or sell copies of the Software, and to |
12 | | ** permit persons to whom the Software is furnished to do so, subject to |
13 | | ** the following conditions: |
14 | | ** |
15 | | ** The above copyright notice and this permission notice shall be |
16 | | ** included in all copies or substantial portions of the Software. |
17 | | ** |
18 | | ** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
19 | | ** EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
20 | | ** MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. |
21 | | ** IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY |
22 | | ** CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, |
23 | | ** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE |
24 | | ** SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
25 | | */ |
26 | | |
27 | | #include "proj.h" |
28 | | #include "proj_internal.h" |
29 | | #include <errno.h> |
30 | | #include <math.h> |
31 | | |
32 | | namespace { // anonymous namespace |
33 | | struct pj_opaque { |
34 | | double phic0; |
35 | | double cosc0, sinc0; |
36 | | double R2; |
37 | | void *en; |
38 | | }; |
39 | | } // anonymous namespace |
40 | | |
41 | | PROJ_HEAD(sterea, "Oblique Stereographic Alternative") "\n\tAzimuthal, Sph&Ell"; |
42 | | |
43 | 0 | static PJ_XY sterea_e_forward(PJ_LP lp, PJ *P) { /* Ellipsoidal, forward */ |
44 | 0 | PJ_XY xy = {0.0, 0.0}; |
45 | 0 | struct pj_opaque *Q = static_cast<struct pj_opaque *>(P->opaque); |
46 | 0 | double cosc, sinc, cosl, k; |
47 | |
|
48 | 0 | lp = pj_gauss(P->ctx, lp, Q->en); |
49 | 0 | sinc = sin(lp.phi); |
50 | 0 | cosc = cos(lp.phi); |
51 | 0 | cosl = cos(lp.lam); |
52 | 0 | const double denom = 1. + Q->sinc0 * sinc + Q->cosc0 * cosc * cosl; |
53 | 0 | if (denom == 0.0) { |
54 | 0 | proj_errno_set(P, PROJ_ERR_COORD_TRANSFM_OUTSIDE_PROJECTION_DOMAIN); |
55 | 0 | return proj_coord_error().xy; |
56 | 0 | } |
57 | 0 | k = P->k0 * Q->R2 / denom; |
58 | 0 | xy.x = k * cosc * sin(lp.lam); |
59 | 0 | xy.y = k * (Q->cosc0 * sinc - Q->sinc0 * cosc * cosl); |
60 | 0 | return xy; |
61 | 0 | } |
62 | | |
63 | 0 | static PJ_LP sterea_e_inverse(PJ_XY xy, PJ *P) { /* Ellipsoidal, inverse */ |
64 | 0 | PJ_LP lp = {0.0, 0.0}; |
65 | 0 | struct pj_opaque *Q = static_cast<struct pj_opaque *>(P->opaque); |
66 | 0 | double rho, c, sinc, cosc; |
67 | |
|
68 | 0 | xy.x /= P->k0; |
69 | 0 | xy.y /= P->k0; |
70 | 0 | if ((rho = hypot(xy.x, xy.y)) != 0.0) { |
71 | 0 | c = 2. * atan2(rho, Q->R2); |
72 | 0 | sinc = sin(c); |
73 | 0 | cosc = cos(c); |
74 | 0 | lp.phi = asin(cosc * Q->sinc0 + xy.y * sinc * Q->cosc0 / rho); |
75 | 0 | lp.lam = |
76 | 0 | atan2(xy.x * sinc, rho * Q->cosc0 * cosc - xy.y * Q->sinc0 * sinc); |
77 | 0 | } else { |
78 | 0 | lp.phi = Q->phic0; |
79 | 0 | lp.lam = 0.; |
80 | 0 | } |
81 | 0 | return pj_inv_gauss(P->ctx, lp, Q->en); |
82 | 0 | } |
83 | | |
84 | 53 | static PJ *destructor(PJ *P, int errlev) { |
85 | 53 | if (nullptr == P) |
86 | 0 | return nullptr; |
87 | | |
88 | 53 | if (nullptr == P->opaque) |
89 | 0 | return pj_default_destructor(P, errlev); |
90 | | |
91 | 53 | free(static_cast<struct pj_opaque *>(P->opaque)->en); |
92 | 53 | return pj_default_destructor(P, errlev); |
93 | 53 | } |
94 | | |
95 | 53 | PJ *PJ_PROJECTION(sterea) { |
96 | 53 | double R; |
97 | 53 | struct pj_opaque *Q = |
98 | 53 | static_cast<struct pj_opaque *>(calloc(1, sizeof(struct pj_opaque))); |
99 | | |
100 | 53 | if (nullptr == Q) |
101 | 0 | return pj_default_destructor(P, PROJ_ERR_OTHER /*ENOMEM*/); |
102 | 53 | P->opaque = Q; |
103 | | |
104 | 53 | Q->en = pj_gauss_ini(P->e, P->phi0, &(Q->phic0), &R); |
105 | 53 | if (nullptr == Q->en) |
106 | 0 | return pj_default_destructor(P, PROJ_ERR_OTHER /*ENOMEM*/); |
107 | | |
108 | 53 | Q->sinc0 = sin(Q->phic0); |
109 | 53 | Q->cosc0 = cos(Q->phic0); |
110 | 53 | Q->R2 = 2. * R; |
111 | | |
112 | 53 | P->inv = sterea_e_inverse; |
113 | 53 | P->fwd = sterea_e_forward; |
114 | 53 | P->destructor = destructor; |
115 | | |
116 | 53 | return P; |
117 | 53 | } |