New

git-svn-id: http://svn.osgeo.org/metacrs/proj/trunk@776 4e78687f-474d-0410-85f9-8d5e500ac6b2

1 files changed, 241 insertions, 0 deletions

diff --git a/src/PJ_aeqd.c b/src/PJ_aeqd.c
new file mode 100644
index 00000000..95f98722
--- /dev/null
+++ b/src/PJ_aeqd.c
@@ -0,0 +1,241 @@
+#ifndef lint
+static const char SCCSID[]="@(#)PJ_aeqd.c	4.3	94/11/03	GIE	REL";
+#endif
+#define EPS10 1.e-10
+#define TOL 1.e-14
+#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>
+PROJ_HEAD(aeqd, "Azimuthal Equidistant") "\n\tAzi, Sph&Ell\n\tlat_0 guam";
+#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;
+	int i;
+
+	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)