1 /*
2 ** libproj -- library of cartographic projections
3 **
4 ** Copyright (c) 2003, 2006   Gerald I. Evenden
5 */
6 static const char
7 LIBPROJ_ID[] = "Id";
8 /*
9 ** Permission is hereby granted, free of charge, to any person obtaining
10 ** a copy of this software and associated documentation files (the
11 ** "Software"), to deal in the Software without restriction, including
12 ** without limitation the rights to use, copy, modify, merge, publish,
13 ** distribute, sublicense, and/or sell copies of the Software, and to
14 ** permit persons to whom the Software is furnished to do so, subject to
15 ** the following conditions:
16 **
17 ** The above copyright notice and this permission notice shall be
18 ** included in all copies or substantial portions of the Software.
19 **
20 ** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
21 ** EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
22 ** MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
23 ** IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
24 ** CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
25 ** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
26 ** SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
27 */
28 #define PROJ_PARMS__ \
29   double  cosphi1;
30 #define PROJ_LIB__
31 # include  <lib_proj.h>
32 PROJ_HEAD(wink2, "Winkel II") "\n\tPCyl., Sph., no inv.\n\tlat_1=";
33 #define MAX_ITER    10
34 #define LOOP_TOL    1e-7
35 #define TWO_D_PI 0.636619772367581343
36 FORWARD(s_forward); /* spheroid */
37   double k, V;
38   int i;
39 
40   xy.y = lp.phi * TWO_D_PI;
41   k = PI * sin(lp.phi);
42   lp.phi *= 1.8;
43   for (i = MAX_ITER; i ; --i) {
44     lp.phi -= V = (lp.phi + sin(lp.phi) - k) /
45       (1. + cos(lp.phi));
46     if (fabs(V) < LOOP_TOL)
47       break;
48   }
49   if (!i)
50     lp.phi = (lp.phi < 0.) ? -HALFPI : HALFPI;
51   else
52     lp.phi *= 0.5;
53   xy.x = 0.5 * lp.lam * (cos(lp.phi) + P->cosphi1);
54   xy.y = FORTPI * (sin(lp.phi) + xy.y);
55   return (xy);
56 }
57 FREEUP; if (P) free(P); }
58 ENTRY0(wink2)
59   P->cosphi1 = cos(proj_param(P->params, "rlat_1").f);
60   P->es = 0.; P->inv = 0; P->fwd = s_forward;
61 ENDENTRY(P)
62 /*
63 ** Log: proj_wink2.c
64 ** Revision 3.1  2006/01/11 01:38:18  gie
65 ** Initial
66 **
67 */
68