New

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

1 files changed, 69 insertions, 0 deletions

diff --git a/src/PJ_somerc.c b/src/PJ_somerc.c
new file mode 100644
index 00000000..4be9f085
--- /dev/null
+++ b/src/PJ_somerc.c
@@ -0,0 +1,69 @@
+#ifndef lint
+static const char SCCSID[]="@(#)PJ_somerc.c	4.1	95/08/09	GIE	REL";
+#endif
+#define PROJ_PARMS__ \
+	double	K, c, hlf_e, kR, cosp0, sinp0;
+#define PJ_LIB__
+#include	<projects.h>
+PROJ_HEAD(somerc, "Swiss. Obl. Mercator") "\n\tCyl, Ell\n\tFor CH1903";
+#define EPS	1.e-10
+#define NITER 6
+FORWARD(e_forward);
+	double phip, lamp, phipp, lampp, sp, cp;
+
+	sp = P->e * sin(lp.phi);
+	phip = 2.* atan( exp( P->c * (
+		log(tan(FORTPI + 0.5 * lp.phi)) - P->hlf_e * log((1. + sp)/(1. - sp)))
+		+ P->K)) - HALFPI;
+	lamp = P->c * lp.lam;
+	cp = cos(phip);
+	phipp = aasin(P->cosp0 * sin(phip) - P->sinp0 * cp * cos(lamp));
+	lampp = aasin(cp * sin(lamp) / cos(phipp));
+	xy.x = P->kR * lampp;
+	xy.y = P->kR * log(tan(FORTPI + 0.5 * phipp));
+	return (xy);
+}
+INVERSE(e_inverse); /* ellipsoid & spheroid */
+	double phip, lamp, phipp, lampp, cp, esp, con, delp;
+	int i;
+
+	phipp = 2. * (atan(exp(xy.y / P->kR)) - FORTPI);
+	lampp = xy.x / P->kR;
+	cp = cos(phipp);
+	phip = aasin(P->cosp0 * sin(phipp) + P->sinp0 * cp * cos(lampp));
+	lamp = aasin(cp * sin(lampp) / cos(phip));
+	con = (P->K - log(tan(FORTPI + 0.5 * phip)))/P->c;
+	for (i = NITER; i ; --i) {
+		esp = P->e * sin(phip);
+		delp = (con + log(tan(FORTPI + 0.5 * phip)) - P->hlf_e *
+			log((1. + esp)/(1. - esp)) ) *
+			(1. - esp * esp) * cos(phip) * P->rone_es;
+		phip -= delp;
+		if (fabs(delp) < EPS)
+			break;
+	}
+	if (i) {
+		lp.phi = phip;
+		lp.lam = lamp / P->c;
+	} else
+		I_ERROR
+	return (lp);
+}
+FREEUP; if (P) pj_dalloc(P); }
+ENTRY0(somerc)
+	double cp, phip0, sp;
+
+	P->hlf_e = 0.5 * P->e;
+	cp = cos(P->phi0);
+	cp *= cp;
+	P->c = sqrt(1 + P->es * cp * cp * P->rone_es);
+	sp = sin(P->phi0);
+	P->cosp0 = cos( phip0 = aasin(P->sinp0 = sp / P->c) );
+	sp *= P->e;
+	P->K = log(tan(FORTPI + 0.5 * phip0)) - P->c * (
+		log(tan(FORTPI + 0.5 * P->phi0)) - P->hlf_e *
+		log((1. + sp) / (1. - sp)));
+	P->kR = P->k0 * sqrt(P->one_es) / (1. - sp * sp);
+	P->inv = e_inverse;
+	P->fwd = e_forward;
+ENDENTRY(P)