/Proj4/PJ_cass.c
C | 82 lines | 81 code | 1 blank | 0 comment | 5 complexity | ae3dae96ab70eb78789fe671ff78d8dd MD5 | raw file
- #ifndef lint
- static const char SCCSID[]="@(#)PJ_cass.c 4.1 94/02/15 GIE REL";
- #endif
- #define PROJ_PARMS__ \
- double m0; \
- double n; \
- double t; \
- double a1; \
- double c; \
- double r; \
- double dd; \
- double d2; \
- double a2; \
- double tn; \
- double *en;
- #define PJ_LIB__
- # include "projects.h"
- PROJ_HEAD(cass, "Cassini") "\n\tCyl, Sph&Ell";
- # define EPS10 1e-10
- # define C1 .16666666666666666666
- # define C2 .00833333333333333333
- # define C3 .04166666666666666666
- # define C4 .33333333333333333333
- # define C5 .06666666666666666666
- FORWARD(e_forward); /* ellipsoid */
- xy.y = pj_mlfn(lp.phi, P->n = sin(lp.phi), P->c = cos(lp.phi), P->en);
- P->n = 1./sqrt(1. - P->es * P->n * P->n);
- P->tn = tan(lp.phi); P->t = P->tn * P->tn;
- P->a1 = lp.lam * P->c;
- P->c *= P->es * P->c / (1 - P->es);
- P->a2 = P->a1 * P->a1;
- xy.x = P->n * P->a1 * (1. - P->a2 * P->t *
- (C1 - (8. - P->t + 8. * P->c) * P->a2 * C2));
- xy.y -= P->m0 - P->n * P->tn * P->a2 *
- (.5 + (5. - P->t + 6. * P->c) * P->a2 * C3);
- return (xy);
- }
- FORWARD(s_forward); /* spheroid */
- xy.x = asin(cos(lp.phi) * sin(lp.lam));
- xy.y = atan2(tan(lp.phi) , cos(lp.lam)) - P->phi0;
- return (xy);
- }
- INVERSE(e_inverse); /* ellipsoid */
- double ph1;
- ph1 = pj_inv_mlfn(P->m0 + xy.y, P->es, P->en);
- P->tn = tan(ph1); P->t = P->tn * P->tn;
- P->n = sin(ph1);
- P->r = 1. / (1. - P->es * P->n * P->n);
- P->n = sqrt(P->r);
- P->r *= (1. - P->es) * P->n;
- P->dd = xy.x / P->n;
- P->d2 = P->dd * P->dd;
- lp.phi = ph1 - (P->n * P->tn / P->r) * P->d2 *
- (.5 - (1. + 3. * P->t) * P->d2 * C3);
- lp.lam = P->dd * (1. + P->t * P->d2 *
- (-C4 + (1. + 3. * P->t) * P->d2 * C5)) / cos(ph1);
- return (lp);
- }
- INVERSE(s_inverse); /* spheroid */
- lp.phi = asin(sin(P->dd = xy.y + P->phi0) * cos(xy.x));
- lp.lam = atan2(tan(xy.x), cos(P->dd));
- return (lp);
- }
- FREEUP;
- if (P) {
- if (P->en)
- pj_dalloc(P->en);
- pj_dalloc(P);
- }
- }
- ENTRY1(cass, en)
- if (P->es) {
- if (!(P->en = pj_enfn(P->es))) E_ERROR_0;
- P->m0 = pj_mlfn(P->phi0, sin(P->phi0), cos(P->phi0), P->en);
- P->inv = e_inverse;
- P->fwd = e_forward;
- } else {
- P->inv = s_inverse;
- P->fwd = s_forward;
- }
- ENDENTRY(P)