/Proj4/PJ_tmerc.c
C | 148 lines | 143 code | 5 blank | 0 comment | 22 complexity | e34753a3c0172d7c2f4850c9462f3595 MD5 | raw file
- #ifndef lint
- static const char SCCSID[]="@(#)PJ_tmerc.c 4.2 94/06/02 GIE REL";
- #endif
- #define PROJ_PARMS__ \
- double esp; \
- double ml0; \
- double *en;
- #define PJ_LIB__
- #include "projects.h"
- PROJ_HEAD(tmerc, "Transverse Mercator") "\n\tCyl, Sph&Ell";
- PROJ_HEAD(utm, "Universal Transverse Mercator (UTM)")
- "\n\tCyl, Sph\n\tzone= south";
- #define EPS10 1.e-10
- #define aks0 P->esp
- #define aks5 P->ml0
- #define FC1 1.
- #define FC2 .5
- #define FC3 .16666666666666666666
- #define FC4 .08333333333333333333
- #define FC5 .05
- #define FC6 .03333333333333333333
- #define FC7 .02380952380952380952
- #define FC8 .01785714285714285714
- FORWARD(e_forward); /* ellipse */
- double al, als, n, cosphi, sinphi, t;
- sinphi = sin(lp.phi); cosphi = cos(lp.phi);
- t = fabs(cosphi) > 1e-10 ? sinphi/cosphi : 0.;
- t *= t;
- al = cosphi * lp.lam;
- als = al * al;
- al /= sqrt(1. - P->es * sinphi * sinphi);
- n = P->esp * cosphi * cosphi;
- xy.x = P->k0 * al * (FC1 +
- FC3 * als * (1. - t + n +
- FC5 * als * (5. + t * (t - 18.) + n * (14. - 58. * t)
- + FC7 * als * (61. + t * ( t * (179. - t) - 479. ) )
- )));
- xy.y = P->k0 * (pj_mlfn(lp.phi, sinphi, cosphi, P->en) - P->ml0 +
- sinphi * al * lp.lam * FC2 * ( 1. +
- FC4 * als * (5. - t + n * (9. + 4. * n) +
- FC6 * als * (61. + t * (t - 58.) + n * (270. - 330 * t)
- + FC8 * als * (1385. + t * ( t * (543. - t) - 3111.) )
- ))));
- return (xy);
- }
- FORWARD(s_forward); /* sphere */
- double b, cosphi;
- b = (cosphi = cos(lp.phi)) * sin(lp.lam);
- if (fabs(fabs(b) - 1.) <= EPS10) F_ERROR;
- xy.x = aks5 * log((1. + b) / (1. - b));
- if ((b = fabs( xy.y = cosphi * cos(lp.lam) / sqrt(1. - b * b) )) >= 1.) {
- if ((b - 1.) > EPS10) F_ERROR
- else xy.y = 0.;
- } else
- xy.y = acos(xy.y);
- if (lp.phi < 0.) xy.y = -xy.y;
- xy.y = aks0 * (xy.y - P->phi0);
- return (xy);
- }
- INVERSE(e_inverse); /* ellipsoid */
- double n, con, cosphi, d, ds, sinphi, t;
- lp.phi = pj_inv_mlfn(P->ml0 + xy.y / P->k0, P->es, P->en);
- if (fabs(lp.phi) >= HALFPI) {
- lp.phi = xy.y < 0. ? -HALFPI : HALFPI;
- lp.lam = 0.;
- } else {
- sinphi = sin(lp.phi);
- cosphi = cos(lp.phi);
- t = fabs(cosphi) > 1e-10 ? sinphi/cosphi : 0.;
- n = P->esp * cosphi * cosphi;
- d = xy.x * sqrt(con = 1. - P->es * sinphi * sinphi) / P->k0;
- con *= t;
- t *= t;
- ds = d * d;
- lp.phi -= (con * ds / (1.-P->es)) * FC2 * (1. -
- ds * FC4 * (5. + t * (3. - 9. * n) + n * (1. - 4 * n) -
- ds * FC6 * (61. + t * (90. - 252. * n +
- 45. * t) + 46. * n
- - ds * FC8 * (1385. + t * (3633. + t * (4095. + 1574. * t)) )
- )));
- lp.lam = d*(FC1 -
- ds*FC3*( 1. + 2.*t + n -
- ds*FC5*(5. + t*(28. + 24.*t + 8.*n) + 6.*n
- - ds * FC7 * (61. + t * (662. + t * (1320. + 720. * t)) )
- ))) / cosphi;
- }
- return (lp);
- }
- INVERSE(s_inverse); /* sphere */
- double h, g;
- h = exp(xy.x / aks0);
- g = .5 * (h - 1. / h);
- h = cos(P->phi0 + xy.y / aks0);
- lp.phi = asin(sqrt((1. - h * h) / (1. + g * g)));
- if (xy.y < 0.) lp.phi = -lp.phi;
- lp.lam = (g || h) ? atan2(g, h) : 0.;
- return (lp);
- }
- FREEUP;
- if (P) {
- if (P->en)
- pj_dalloc(P->en);
- pj_dalloc(P);
- }
- }
- static PJ *
- setup(PJ *P) { /* general initialization */
- if (P->es) {
- if (!(P->en = pj_enfn(P->es)))
- E_ERROR_0;
- P->ml0 = pj_mlfn(P->phi0, sin(P->phi0), cos(P->phi0), P->en);
- P->esp = P->es / (1. - P->es);
- P->inv = e_inverse;
- P->fwd = e_forward;
- } else {
- aks0 = P->k0;
- aks5 = .5 * aks0;
- P->inv = s_inverse;
- P->fwd = s_forward;
- }
- return P;
- }
- ENTRY1(tmerc, en)
- ENDENTRY(setup(P))
- ENTRY1(utm, en)
- int zone;
- if (!P->es) E_ERROR(-34);
- P->y0 = pj_param(P->params, "bsouth").i ? 10000000. : 0.;
- P->x0 = 500000.;
- if (pj_param(P->params, "tzone").i) /* zone input ? */
- if ((zone = pj_param(P->params, "izone").i) > 0 && zone <= 60)
- --zone;
- else
- E_ERROR(-35)
- else /* nearest central meridian input */
- if ((zone = floor((adjlon(P->lam0) + PI) * 30. / PI)) < 0)
- zone = 0;
- else if (zone >= 60)
- zone = 59;
- P->lam0 = (zone + .5) * PI / 30. - PI;
- P->k0 = 0.9996;
- P->phi0 = 0.;
- ENDENTRY(setup(P))