/Proj4/PJ_gn_sinu.c
http://github.com/route-me/route-me · C · 103 lines · 97 code · 4 blank · 2 comment · 18 complexity · d256ab339699281799f1be84cd4296db MD5 · raw file
- #ifndef lint
- static const char SCCSID[]="@(#)PJ_gn_sinu.c 4.1 94/02/15 GIE REL";
- #endif
- #define PROJ_PARMS__ \
- double *en; \
- double m, n, C_x, C_y;
- #define PJ_LIB__
- #include "projects.h"
- PROJ_HEAD(gn_sinu, "General Sinusoidal Series") "\n\tPCyl, Sph.\n\tm= n=";
- PROJ_HEAD(sinu, "Sinusoidal (Sanson-Flamsteed)") "\n\tPCyl, Sph&Ell";
- PROJ_HEAD(eck6, "Eckert VI") "\n\tPCyl, Sph.";
- PROJ_HEAD(mbtfps, "McBryde-Thomas Flat-Polar Sinusoidal") "\n\tPCyl, Sph.";
- #define EPS10 1e-10
- #define MAX_ITER 8
- #define LOOP_TOL 1e-7
- /* Ellipsoidal Sinusoidal only */
- FORWARD(e_forward); /* ellipsoid */
- double s, c;
- xy.y = pj_mlfn(lp.phi, s = sin(lp.phi), c = cos(lp.phi), P->en);
- xy.x = lp.lam * c / sqrt(1. - P->es * s * s);
- return (xy);
- }
- INVERSE(e_inverse); /* ellipsoid */
- double s;
- if ((s = fabs(lp.phi = pj_inv_mlfn(xy.y, P->es, P->en))) < HALFPI) {
- s = sin(lp.phi);
- lp.lam = xy.x * sqrt(1. - P->es * s * s) / cos(lp.phi);
- } else if ((s - EPS10) < HALFPI)
- lp.lam = 0.;
- else I_ERROR;
- return (lp);
- }
- /* General spherical sinusoidals */
- FORWARD(s_forward); /* sphere */
- if (!P->m)
- lp.phi = P->n != 1. ? aasin(P->n * sin(lp.phi)): lp.phi;
- else {
- double k, V;
- int i;
- k = P->n * sin(lp.phi);
- for (i = MAX_ITER; i ; --i) {
- lp.phi -= V = (P->m * lp.phi + sin(lp.phi) - k) /
- (P->m + cos(lp.phi));
- if (fabs(V) < LOOP_TOL)
- break;
- }
- if (!i)
- F_ERROR
- }
- xy.x = P->C_x * lp.lam * (P->m + cos(lp.phi));
- xy.y = P->C_y * lp.phi;
- return (xy);
- }
- INVERSE(s_inverse); /* sphere */
- double s;
- xy.y /= P->C_y;
- lp.phi = P->m ? aasin((P->m * xy.y + sin(xy.y)) / P->n) :
- ( P->n != 1. ? aasin(sin(xy.y) / P->n) : xy.y );
- lp.lam = xy.x / (P->C_x * (P->m + cos(xy.y)));
- return (lp);
- }
- FREEUP; if (P) { if (P->en) pj_dalloc(P->en); pj_dalloc(P); } }
- static void /* for spheres, only */
- setup(PJ *P) {
- P->es = 0;
- P->C_x = (P->C_y = sqrt((P->m + 1.) / P->n))/(P->m + 1.);
- P->inv = s_inverse;
- P->fwd = s_forward;
- }
- ENTRY1(sinu, en)
- if (!(P->en = pj_enfn(P->es)))
- E_ERROR_0;
- if (P->es) {
- P->inv = e_inverse;
- P->fwd = e_forward;
- } else {
- P->n = 1.;
- P->m = 0.;
- setup(P);
- }
- ENDENTRY(P)
- ENTRY1(eck6, en)
- P->m = 1.;
- P->n = 2.570796326794896619231321691;
- setup(P);
- ENDENTRY(P)
- ENTRY1(mbtfps, en)
- P->m = 0.5;
- P->n = 1.785398163397448309615660845;
- setup(P);
- ENDENTRY(P)
- ENTRY1(gn_sinu, en)
- if (pj_param(P->params, "tn").i && pj_param(P->params, "tm").i) {
- P->n = pj_param(P->params, "dn").f;
- P->m = pj_param(P->params, "dm").f;
- } else
- E_ERROR(-99)
- setup(P);
- ENDENTRY(P)