svn-gvsig-desktop / trunk / libraries / libjni-proj4 / src / PJ_omerc.c @ 7098
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#ifndef lint
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static const char SCCSID[]="@(#)PJ_omerc.c 4.2 95/01/01 GIE REL"; |
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#endif
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#define PROJ_PARMS__ \
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double alpha, lamc, lam1, phi1, lam2, phi2, Gamma, al, bl, el, \
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singam, cosgam, sinrot, cosrot, u_0; \ |
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int ellips, rot;
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#define PJ_LIB__
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#include <projects.h> |
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PROJ_HEAD(omerc, "Oblique Mercator")
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"\n\tCyl, Sph&Ell\n\t no_rot rot_conv no_uoff and\n\t"
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"alpha= lonc= or\n\t lon_1= lat_1= lon_2= lat_2=";
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#define TOL 1.e-7 |
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#define EPS 1.e-10 |
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#define TSFN0(x) tan(.5 * (HALFPI - (x))) |
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FORWARD(e_forward); /* ellipsoid & spheroid */
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double con, q, s, ul, us, vl, vs;
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vl = sin(P->bl * lp.lam); |
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if (fabs(fabs(lp.phi) - HALFPI) <= EPS) {
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ul = lp.phi < 0. ? -P->singam : P->singam;
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us = P->al * lp.phi / P->bl; |
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} else {
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q = P->el / (P->ellips ? pow(pj_tsfn(lp.phi, sin(lp.phi), P->e), P->bl) |
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: TSFN0(lp.phi)); |
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s = .5 * (q - 1. / q); |
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ul = 2. * (s * P->singam - vl * P->cosgam) / (q + 1. / q); |
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con = cos(P->bl * lp.lam); |
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if (fabs(con) >= TOL) {
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us = P->al * atan((s * P->cosgam + vl * P->singam) / con) / P->bl; |
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if (con < 0.) |
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us += PI * P->al / P->bl; |
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} else
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us = P->al * P->bl * lp.lam; |
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} |
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if (fabs(fabs(ul) - 1.) <= EPS) F_ERROR; |
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vs = .5 * P->al * log((1. - ul) / (1. + ul)) / P->bl; |
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us -= P->u_0; |
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if (! P->rot) {
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xy.x = us; |
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xy.y = vs; |
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} else {
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xy.x = vs * P->cosrot + us * P->sinrot; |
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xy.y = us * P->cosrot - vs * P->sinrot; |
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} |
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return (xy);
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} |
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INVERSE(e_inverse); /* ellipsoid & spheroid */
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double q, s, ul, us, vl, vs;
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if (! P->rot) {
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us = xy.x; |
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vs = xy.y; |
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} else {
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vs = xy.x * P->cosrot - xy.y * P->sinrot; |
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us = xy.y * P->cosrot + xy.x * P->sinrot; |
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} |
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us += P->u_0; |
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q = exp(- P->bl * vs / P->al); |
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s = .5 * (q - 1. / q); |
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vl = sin(P->bl * us / P->al); |
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ul = 2. * (vl * P->cosgam + s * P->singam) / (q + 1. / q); |
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if (fabs(fabs(ul) - 1.) < EPS) { |
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lp.lam = 0.;
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lp.phi = ul < 0. ? -HALFPI : HALFPI;
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} else {
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lp.phi = P->el / sqrt((1. + ul) / (1. - ul)); |
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if (P->ellips) {
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if ((lp.phi = pj_phi2(pow(lp.phi, 1. / P->bl), P->e)) == HUGE_VAL) |
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I_ERROR; |
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} else
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lp.phi = HALFPI - 2. * atan(lp.phi);
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lp.lam = - atan2((s * P->cosgam - |
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vl * P->singam), cos(P->bl * us / P->al)) / P->bl; |
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} |
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return (lp);
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} |
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FREEUP; if (P) pj_dalloc(P); }
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ENTRY0(omerc) |
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double con, com, cosph0, d, f, h, l, sinph0, p, j;
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int azi;
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P->rot = pj_param(P->params, "bno_rot").i == 0; |
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if( (azi = pj_param(P->params, "talpha").i) != 0.0) { |
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P->lamc = pj_param(P->params, "rlonc").f;
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P->alpha = pj_param(P->params, "ralpha").f;
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if ( fabs(P->alpha) <= TOL ||
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fabs(fabs(P->phi0) - HALFPI) <= TOL || |
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fabs(fabs(P->alpha) - HALFPI) <= TOL) |
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E_ERROR(-32);
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} else {
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P->lam1 = pj_param(P->params, "rlon_1").f;
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P->phi1 = pj_param(P->params, "rlat_1").f;
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P->lam2 = pj_param(P->params, "rlon_2").f;
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P->phi2 = pj_param(P->params, "rlat_2").f;
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if (fabs(P->phi1 - P->phi2) <= TOL ||
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(con = fabs(P->phi1)) <= TOL || |
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fabs(con - HALFPI) <= TOL || |
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fabs(fabs(P->phi0) - HALFPI) <= TOL || |
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fabs(fabs(P->phi2) - HALFPI) <= TOL) E_ERROR(-33);
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} |
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com = (P->ellips = P->es > 0.) ? sqrt(P->one_es) : 1.; |
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if (fabs(P->phi0) > EPS) {
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sinph0 = sin(P->phi0); |
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cosph0 = cos(P->phi0); |
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if (P->ellips) {
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con = 1. - P->es * sinph0 * sinph0;
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P->bl = cosph0 * cosph0; |
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P->bl = sqrt(1. + P->es * P->bl * P->bl / P->one_es);
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P->al = P->bl * P->k0 * com / con; |
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d = P->bl * com / (cosph0 * sqrt(con)); |
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} else {
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P->bl = 1.;
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P->al = P->k0; |
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d = 1. / cosph0;
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} |
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if ((f = d * d - 1.) <= 0.) |
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f = 0.;
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else {
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f = sqrt(f); |
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if (P->phi0 < 0.) |
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f = -f; |
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} |
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P->el = f += d; |
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if (P->ellips) P->el *= pow(pj_tsfn(P->phi0, sinph0, P->e), P->bl);
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else P->el *= TSFN0(P->phi0);
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} else {
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P->bl = 1. / com;
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P->al = P->k0; |
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P->el = d = f = 1.;
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} |
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if (azi) {
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P->Gamma = asin(sin(P->alpha) / d); |
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P->lam0 = P->lamc - asin((.5 * (f - 1. / f)) * |
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tan(P->Gamma)) / P->bl; |
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} else {
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if (P->ellips) {
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h = pow(pj_tsfn(P->phi1, sin(P->phi1), P->e), P->bl); |
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l = pow(pj_tsfn(P->phi2, sin(P->phi2), P->e), P->bl); |
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} else {
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h = TSFN0(P->phi1); |
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l = TSFN0(P->phi2); |
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} |
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f = P->el / h; |
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p = (l - h) / (l + h); |
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j = P->el * P->el; |
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j = (j - l * h) / (j + l * h); |
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if ((con = P->lam1 - P->lam2) < -PI)
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P->lam2 -= TWOPI; |
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else if (con > PI) |
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P->lam2 += TWOPI; |
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P->lam0 = adjlon(.5 * (P->lam1 + P->lam2) - atan(
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j * tan(.5 * P->bl * (P->lam1 - P->lam2)) / p) / P->bl);
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P->Gamma = atan(2. * sin(P->bl * adjlon(P->lam1 - P->lam0)) /
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(f - 1. / f));
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P->alpha = asin(d * sin(P->Gamma)); |
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} |
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P->singam = sin(P->Gamma); |
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P->cosgam = cos(P->Gamma); |
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f = pj_param(P->params, "brot_conv").i ? P->Gamma : P->alpha;
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P->sinrot = sin(f); |
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P->cosrot = cos(f); |
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P->u_0 = pj_param(P->params, "bno_uoff").i ? 0. : |
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fabs(P->al * atan(sqrt(d * d - 1.) / P->cosrot) / P->bl);
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if (P->phi0 < 0.) |
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P->u_0 = - P->u_0; |
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P->inv = e_inverse; |
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P->fwd = e_forward; |
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ENDENTRY(P) |