New

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

1 files changed, 169 insertions, 0 deletions

diff --git a/src/PJ_omerc.c b/src/PJ_omerc.c
new file mode 100644
index 00000000..5494186b
--- /dev/null
+++ b/src/PJ_omerc.c
@@ -0,0 +1,169 @@
+#ifndef lint
+static const char SCCSID[]="@(#)PJ_omerc.c	4.2	95/01/01	GIE	REL";
+#endif
+#define PROJ_PARMS__ \
+	double	alpha, lamc, lam1, phi1, lam2, phi2, Gamma, al, bl, el, \
+		singam, cosgam, sinrot, cosrot, u_0; \
+	int		ellips, rot;
+#define PJ_LIB__
+#include	<projects.h>
+PROJ_HEAD(omerc, "Oblique Mercator")
+	"\n\tCyl, Sph&Ell\n\t no_rot rot_conv no_uoff and\n\t"
+"alpha= lonc= or\n\t lon_1= lat_1= lon_2= lat_2=";
+#define TOL	1.e-7
+#define EPS	1.e-10
+#define TSFN0(x)	tan(.5 * (HALFPI - (x)))
+FORWARD(e_forward); /* ellipsoid & spheroid */
+	double  con, q, s, ul, us, vl, vs;
+
+	vl = sin(P->bl * lp.lam);
+	if (fabs(fabs(lp.phi) - HALFPI) <= EPS) {
+		ul = lp.phi < 0. ? -P->singam : P->singam;
+		us = P->al * lp.phi / P->bl;
+	} else {
+		q = P->el / (P->ellips ? pow(pj_tsfn(lp.phi, sin(lp.phi), P->e), P->bl)
+			: TSFN0(lp.phi));
+		s = .5 * (q - 1. / q);
+		ul = 2. * (s * P->singam - vl * P->cosgam) / (q + 1. / q);
+		con = cos(P->bl * lp.lam);
+		if (fabs(con) >= TOL) {
+			us = P->al * atan((s * P->cosgam + vl * P->singam) / con) / P->bl;
+			if (con < 0.)
+				us += PI * P->al / P->bl;
+		} else
+			us = P->al * P->bl * lp.lam;
+	}
+	if (fabs(fabs(ul) - 1.) <= EPS) F_ERROR;
+	vs = .5 * P->al * log((1. - ul) / (1. + ul)) / P->bl;
+	us -= P->u_0;
+	if (! P->rot) {
+		xy.x = us;
+		xy.y = vs;
+	} else {
+		xy.x = vs * P->cosrot + us * P->sinrot;
+		xy.y = us * P->cosrot - vs * P->sinrot;
+	}
+	return (xy);
+}
+INVERSE(e_inverse); /* ellipsoid & spheroid */
+	double  q, s, ul, us, vl, vs;
+
+	if (! P->rot) {
+		us = xy.x;
+		vs = xy.y;
+	} else {
+		vs = xy.x * P->cosrot - xy.y * P->sinrot;
+		us = xy.y * P->cosrot + xy.x * P->sinrot;
+	}
+	us += P->u_0;
+	q = exp(- P->bl * vs / P->al);
+	s = .5 * (q - 1. / q);
+	vl = sin(P->bl * us / P->al);
+	ul = 2. * (vl * P->cosgam + s * P->singam) / (q + 1. / q);
+	if (fabs(fabs(ul) - 1.) < EPS) {
+		lp.lam = 0.;
+		lp.phi = ul < 0. ? -HALFPI : HALFPI;
+	} else {
+		lp.phi = P->el / sqrt((1. + ul) / (1. - ul));
+		if (P->ellips) {
+			if ((lp.phi = pj_phi2(pow(lp.phi, 1. / P->bl), P->e)) == HUGE_VAL)
+				I_ERROR;
+		} else
+			lp.phi = HALFPI - 2. * atan(lp.phi);
+		lp.lam = - atan2((s * P->cosgam -
+			vl * P->singam), cos(P->bl * us / P->al)) / P->bl;
+	}
+	return (lp);
+}
+FREEUP; if (P) pj_dalloc(P); }
+ENTRY0(omerc)
+	double con, com, cosph0, d, f, h, l, sinph0, p, j;
+	int azi;
+
+	P->rot	= pj_param(P->params, "bno_rot").i == 0;
+	if (azi	= pj_param(P->params, "talpha").i) {
+		P->lamc	= pj_param(P->params, "rlonc").f;
+		P->alpha	= pj_param(P->params, "ralpha").f;
+		if ( fabs(P->alpha) <= TOL ||
+			fabs(fabs(P->phi0) - HALFPI) <= TOL ||
+			fabs(fabs(P->alpha) - HALFPI) <= TOL)
+			E_ERROR(-32);
+	} else {
+		P->lam1	= pj_param(P->params, "rlon_1").f;
+		P->phi1	= pj_param(P->params, "rlat_1").f;
+		P->lam2	= pj_param(P->params, "rlon_2").f;
+		P->phi2	= pj_param(P->params, "rlat_2").f;
+		if (fabs(P->phi1 - P->phi2) <= TOL ||
+			(con = fabs(P->phi1)) <= TOL ||
+			fabs(con - HALFPI) <= TOL ||
+			fabs(fabs(P->phi0) - HALFPI) <= TOL ||
+			fabs(fabs(P->phi2) - HALFPI) <= TOL) E_ERROR(-33);
+	}
+	com = (P->ellips = P->es > 0.) ? sqrt(P->one_es) : 1.;
+	if (fabs(P->phi0) > EPS) {
+		sinph0 = sin(P->phi0);
+		cosph0 = cos(P->phi0);
+		if (P->ellips) {
+			con = 1. - P->es * sinph0 * sinph0;
+			P->bl = cosph0 * cosph0;
+			P->bl = sqrt(1. + P->es * P->bl * P->bl / P->one_es);
+			P->al = P->bl * P->k0 * com / con;
+			d = P->bl * com / (cosph0 * sqrt(con));
+		} else {
+			P->bl = 1.;
+			P->al = P->k0;
+			d = 1. / cosph0;
+		}
+		if ((f = d * d - 1.) <= 0.)
+			f = 0.;
+		else {
+			f = sqrt(f);
+			if (P->phi0 < 0.)
+				f = -f;
+		}
+		P->el = f += d;
+		if (P->ellips)	P->el *= pow(pj_tsfn(P->phi0, sinph0, P->e), P->bl);
+		else		P->el *= TSFN0(P->phi0);
+	} else {
+		P->bl = 1. / com;
+		P->al = P->k0;
+		P->el = d = f = 1.;
+	}
+	if (azi) {
+		P->Gamma = asin(sin(P->alpha) / d);
+		P->lam0 = P->lamc - asin((.5 * (f - 1. / f)) *
+		   tan(P->Gamma)) / P->bl;
+	} else {
+		if (P->ellips) {
+			h = pow(pj_tsfn(P->phi1, sin(P->phi1), P->e), P->bl);
+			l = pow(pj_tsfn(P->phi2, sin(P->phi2), P->e), P->bl);
+		} else {
+			h = TSFN0(P->phi1);
+			l = TSFN0(P->phi2);
+		}
+		f = P->el / h;
+		p = (l - h) / (l + h);
+		j = P->el * P->el;
+		j = (j - l * h) / (j + l * h);
+		if ((con = P->lam1 - P->lam2) < -PI)
+			P->lam2 -= TWOPI;
+		else if (con > PI)
+			P->lam2 += TWOPI;
+		P->lam0 = adjlon(.5 * (P->lam1 + P->lam2) - atan(
+		   j * tan(.5 * P->bl * (P->lam1 - P->lam2)) / p) / P->bl);
+		P->Gamma = atan(2. * sin(P->bl * adjlon(P->lam1 - P->lam0)) /
+		   (f - 1. / f));
+		P->alpha = asin(d * sin(P->Gamma));
+	}
+	P->singam = sin(P->Gamma);
+	P->cosgam = cos(P->Gamma);
+	f = pj_param(P->params, "brot_conv").i ? P->Gamma : P->alpha;
+	P->sinrot = sin(f);
+	P->cosrot = cos(f);
+	P->u_0 = pj_param(P->params, "bno_uoff").i ? 0. :
+		fabs(P->al * atan(sqrt(d * d - 1.) / P->cosrot) / P->bl);
+	if (P->phi0 < 0.)
+		P->u_0 = - P->u_0;
+	P->inv = e_inverse;
+	P->fwd = e_forward;
+ENDENTRY(P)