/Proj4/PJ_aeqd.c
http://github.com/route-me/route-me · C · 277 lines · 232 code · 11 blank · 34 comment · 49 complexity · 734bf86c1287f4407c696e528eacc50b MD5 · raw file
- /******************************************************************************
- * $Id: PJ_aeqd.c,v 1.3 2002/12/14 19:27:06 warmerda Exp $
- *
- * Project: PROJ.4
- * Purpose: Implementation of the aeqd (Azimuthal Equidistant) projection.
- * Author: Gerald Evenden
- *
- ******************************************************************************
- * Copyright (c) 1995, Gerald Evenden
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included
- * in all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
- * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- ******************************************************************************
- *
- * $Log: PJ_aeqd.c,v $
- * Revision 1.3 2002/12/14 19:27:06 warmerda
- * updated header
- *
- */
- #define PROJ_PARMS__ \
- double sinph0; \
- double cosph0; \
- double *en; \
- double M1; \
- double N1; \
- double Mp; \
- double He; \
- double G; \
- int mode;
- #define PJ_LIB__
- #include "projects.h"
- PJ_CVSID("$Id: PJ_aeqd.c,v 1.3 2002/12/14 19:27:06 warmerda Exp $");
- PROJ_HEAD(aeqd, "Azimuthal Equidistant") "\n\tAzi, Sph&Ell\n\tlat_0 guam";
- #define EPS10 1.e-10
- #define TOL 1.e-14
- #define N_POLE 0
- #define S_POLE 1
- #define EQUIT 2
- #define OBLIQ 3
- FORWARD(e_guam_fwd); /* Guam elliptical */
- double cosphi, sinphi, t;
- cosphi = cos(lp.phi);
- sinphi = sin(lp.phi);
- t = 1. / sqrt(1. - P->es * sinphi * sinphi);
- xy.x = lp.lam * cosphi * t;
- xy.y = pj_mlfn(lp.phi, sinphi, cosphi, P->en) - P->M1 +
- .5 * lp.lam * lp.lam * cosphi * sinphi * t;
- return (xy);
- }
- FORWARD(e_forward); /* elliptical */
- double coslam, cosphi, sinphi, rho, s, H, H2, c, Az, t, ct, st, cA, sA;
- coslam = cos(lp.lam);
- cosphi = cos(lp.phi);
- sinphi = sin(lp.phi);
- switch (P->mode) {
- case N_POLE:
- coslam = - coslam;
- case S_POLE:
- xy.x = (rho = fabs(P->Mp - pj_mlfn(lp.phi, sinphi, cosphi, P->en))) *
- sin(lp.lam);
- xy.y = rho * coslam;
- break;
- case EQUIT:
- case OBLIQ:
- if (fabs(lp.lam) < EPS10 && fabs(lp.phi - P->phi0) < EPS10) {
- xy.x = xy.y = 0.;
- break;
- }
- t = atan2(P->one_es * sinphi + P->es * P->N1 * P->sinph0 *
- sqrt(1. - P->es * sinphi * sinphi), cosphi);
- ct = cos(t); st = sin(t);
- Az = atan2(sin(lp.lam) * ct, P->cosph0 * st - P->sinph0 * coslam * ct);
- cA = cos(Az); sA = sin(Az);
- s = aasin( fabs(sA) < TOL ?
- (P->cosph0 * st - P->sinph0 * coslam * ct) / cA :
- sin(lp.lam) * ct / sA );
- H = P->He * cA;
- H2 = H * H;
- c = P->N1 * s * (1. + s * s * (- H2 * (1. - H2)/6. +
- s * ( P->G * H * (1. - 2. * H2 * H2) / 8. +
- s * ((H2 * (4. - 7. * H2) - 3. * P->G * P->G * (1. - 7. * H2)) /
- 120. - s * P->G * H / 48.))));
- xy.x = c * sA;
- xy.y = c * cA;
- break;
- }
- return (xy);
- }
- FORWARD(s_forward); /* spherical */
- double coslam, cosphi, sinphi;
- sinphi = sin(lp.phi);
- cosphi = cos(lp.phi);
- coslam = cos(lp.lam);
- switch (P->mode) {
- case EQUIT:
- xy.y = cosphi * coslam;
- goto oblcon;
- case OBLIQ:
- xy.y = P->sinph0 * sinphi + P->cosph0 * cosphi * coslam;
- oblcon:
- if (fabs(fabs(xy.y) - 1.) < TOL)
- if (xy.y < 0.)
- F_ERROR
- else
- xy.x = xy.y = 0.;
- else {
- xy.y = acos(xy.y);
- xy.y /= sin(xy.y);
- xy.x = xy.y * cosphi * sin(lp.lam);
- xy.y *= (P->mode == EQUIT) ? sinphi :
- P->cosph0 * sinphi - P->sinph0 * cosphi * coslam;
- }
- break;
- case N_POLE:
- lp.phi = -lp.phi;
- coslam = -coslam;
- case S_POLE:
- if (fabs(lp.phi - HALFPI) < EPS10) F_ERROR;
- xy.x = (xy.y = (HALFPI + lp.phi)) * sin(lp.lam);
- xy.y *= coslam;
- break;
- }
- return (xy);
- }
- INVERSE(e_guam_inv); /* Guam elliptical */
- double x2, t;
- int i;
- x2 = 0.5 * xy.x * xy.x;
- lp.phi = P->phi0;
- for (i = 0; i < 3; ++i) {
- t = P->e * sin(lp.phi);
- lp.phi = pj_inv_mlfn(P->M1 + xy.y -
- x2 * tan(lp.phi) * (t = sqrt(1. - t * t)), P->es, P->en);
- }
- lp.lam = xy.x * t / cos(lp.phi);
- return (lp);
- }
- INVERSE(e_inverse); /* elliptical */
- double c, Az, cosAz, A, B, D, E, F, psi, t;
- if ((c = hypot(xy.x, xy.y)) < EPS10) {
- lp.phi = P->phi0;
- lp.lam = 0.;
- return (lp);
- }
- if (P->mode == OBLIQ || P->mode == EQUIT) {
- cosAz = cos(Az = atan2(xy.x, xy.y));
- t = P->cosph0 * cosAz;
- B = P->es * t / P->one_es;
- A = - B * t;
- B *= 3. * (1. - A) * P->sinph0;
- D = c / P->N1;
- E = D * (1. - D * D * (A * (1. + A) / 6. + B * (1. + 3.*A) * D / 24.));
- F = 1. - E * E * (A / 2. + B * E / 6.);
- psi = aasin(P->sinph0 * cos(E) + t * sin(E));
- lp.lam = aasin(sin(Az) * sin(E) / cos(psi));
- if ((t = fabs(psi)) < EPS10)
- lp.phi = 0.;
- else if (fabs(t - HALFPI) < 0.)
- lp.phi = HALFPI;
- else
- lp.phi = atan((1. - P->es * F * P->sinph0 / sin(psi)) * tan(psi) /
- P->one_es);
- } else { /* Polar */
- lp.phi = pj_inv_mlfn(P->mode == N_POLE ? P->Mp - c : P->Mp + c,
- P->es, P->en);
- lp.lam = atan2(xy.x, P->mode == N_POLE ? -xy.y : xy.y);
- }
- return (lp);
- }
- INVERSE(s_inverse); /* spherical */
- double cosc, c_rh, sinc;
- if ((c_rh = hypot(xy.x, xy.y)) > PI) {
- if (c_rh - EPS10 > PI) I_ERROR;
- c_rh = PI;
- } else if (c_rh < EPS10) {
- lp.phi = P->phi0;
- lp.lam = 0.;
- return (lp);
- }
- if (P->mode == OBLIQ || P->mode == EQUIT) {
- sinc = sin(c_rh);
- cosc = cos(c_rh);
- if (P->mode == EQUIT) {
- lp.phi = aasin(xy.y * sinc / c_rh);
- xy.x *= sinc;
- xy.y = cosc * c_rh;
- } else {
- lp.phi = aasin(cosc * P->sinph0 + xy.y * sinc * P->cosph0 /
- c_rh);
- xy.y = (cosc - P->sinph0 * sin(lp.phi)) * c_rh;
- xy.x *= sinc * P->cosph0;
- }
- lp.lam = xy.y == 0. ? 0. : atan2(xy.x, xy.y);
- } else if (P->mode == N_POLE) {
- lp.phi = HALFPI - c_rh;
- lp.lam = atan2(xy.x, -xy.y);
- } else {
- lp.phi = c_rh - HALFPI;
- lp.lam = atan2(xy.x, xy.y);
- }
- return (lp);
- }
- FREEUP;
- if (P) {
- if (P->en)
- pj_dalloc(P->en);
- pj_dalloc(P);
- }
- }
- ENTRY1(aeqd, en)
- P->phi0 = pj_param(P->params, "rlat_0").f;
- if (fabs(fabs(P->phi0) - HALFPI) < EPS10) {
- P->mode = P->phi0 < 0. ? S_POLE : N_POLE;
- P->sinph0 = P->phi0 < 0. ? -1. : 1.;
- P->cosph0 = 0.;
- } else if (fabs(P->phi0) < EPS10) {
- P->mode = EQUIT;
- P->sinph0 = 0.;
- P->cosph0 = 1.;
- } else {
- P->mode = OBLIQ;
- P->sinph0 = sin(P->phi0);
- P->cosph0 = cos(P->phi0);
- }
- if (! P->es) {
- P->inv = s_inverse; P->fwd = s_forward;
- } else {
- if (!(P->en = pj_enfn(P->es))) E_ERROR_0;
- if (pj_param(P->params, "bguam").i) {
- P->M1 = pj_mlfn(P->phi0, P->sinph0, P->cosph0, P->en);
- P->inv = e_guam_inv; P->fwd = e_guam_fwd;
- } else {
- switch (P->mode) {
- case N_POLE:
- P->Mp = pj_mlfn(HALFPI, 1., 0., P->en);
- break;
- case S_POLE:
- P->Mp = pj_mlfn(-HALFPI, -1., 0., P->en);
- break;
- case EQUIT:
- case OBLIQ:
- P->inv = e_inverse; P->fwd = e_forward;
- P->N1 = 1. / sqrt(1. - P->es * P->sinph0 * P->sinph0);
- P->G = P->sinph0 * (P->He = P->e / sqrt(P->one_es));
- P->He *= P->cosph0;
- break;
- }
- P->inv = e_inverse; P->fwd = e_forward;
- }
- }
- ENDENTRY(P)