Application: gvSIG desktop

/******************************************************************************

 * $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)