New

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

1 files changed, 64 insertions, 0 deletions

diff --git a/src/PJ_cea.c b/src/PJ_cea.c
new file mode 100644
index 00000000..4286d9a5
--- /dev/null
+++ b/src/PJ_cea.c
@@ -0,0 +1,64 @@
+#ifndef lint
+static const char SCCSID[]="@(#)PJ_cea.c	4.1	94/02/15	GIE	REL";
+#endif
+#define PROJ_PARMS__ \
+	double qp; \
+	double *apa;
+#define PJ_LIB__
+# include	<projects.h>
+PROJ_HEAD(cea, "Equal Area Cylindrical") "\n\tCyl, Sph&Ell\n\tlat_ts=";
+# define EPS	1e-10
+FORWARD(e_forward); /* spheroid */
+	xy.x = P->k0 * lp.lam;
+	xy.y = .5 * pj_qsfn(sin(lp.phi), P->e, P->one_es) / P->k0;
+	return (xy);
+}
+FORWARD(s_forward); /* spheroid */
+	xy.x = P->k0 * lp.lam;
+	xy.y = sin(lp.phi) / P->k0;
+	return (xy);
+}
+INVERSE(e_inverse); /* spheroid */
+	lp.phi = pj_authlat(asin( 2. * xy.y * P->k0 / P->qp), P->apa);
+	lp.lam = xy.x / P->k0;
+	return (lp);
+}
+INVERSE(s_inverse); /* spheroid */
+	double t;
+
+	if ((t = fabs(xy.y *= P->k0)) - EPS <= 1.) {
+		if (t >= 1.)
+			lp.phi = xy.y < 0. ? -HALFPI : HALFPI;
+		else
+			lp.phi = asin(xy.y);
+		lp.lam = xy.x / P->k0;
+	} else I_ERROR;
+	return (lp);
+}
+FREEUP;
+	if (P) {
+		if (P->apa)
+			pj_dalloc(P->apa);
+		pj_dalloc(P);
+	}
+}
+ENTRY1(cea, apa)
+	double t;
+
+	if (pj_param(P->params, "tlat_ts").i &&
+		(P->k0 = cos(t = pj_param(P->params, "rlat_ts").f)) < 0.) E_ERROR(-24)
+	else
+		t = 0.;
+	if (P->es) {
+		t = sin(t);
+		P->k0 /= sqrt(1. - P->es * t * t);
+		P->e = sqrt(P->es);
+		if (!(P->apa = pj_authset(P->es))) E_ERROR_0;
+		P->qp = pj_qsfn(1., P->e, P->one_es);
+		P->inv = e_inverse;
+		P->fwd = e_forward;
+	} else {
+		P->inv = s_inverse;
+		P->fwd = s_forward;
+	}
+ENDENTRY(P)