From 565a4bd035b9d4a83955808efef20f1d8dfa24cf Mon Sep 17 00:00:00 2001
From: Frank Warmerdam <warmerdam@pobox.com>
Date: Thu, 18 Mar 1999 16:34:52 +0000
Subject: New

git-svn-id: http://svn.osgeo.org/metacrs/proj/trunk@776 4e78687f-474d-0410-85f9-8d5e500ac6b2
---
 src/pj_inv.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 src/pj_inv.c

(limited to 'src/pj_inv.c')

diff --git a/src/pj_inv.c b/src/pj_inv.c
new file mode 100644
index 00000000..16dd90dd
--- /dev/null
+++ b/src/pj_inv.c
@@ -0,0 +1,32 @@
+/* general inverse projection */
+#ifndef lint
+static const char SCCSID[]="@(#)pj_inv.c	4.5	93/06/12	GIE	REL";
+#endif
+#define PJ_LIB__
+#include <projects.h>
+#include <errno.h>
+# define EPS 1.0e-12
+	LP /* inverse projection entry */
+pj_inv(XY xy, PJ *P) {
+	LP lp;
+
+	/* can't do as much preliminary checking as with forward */
+	if (xy.x == HUGE_VAL || xy.y == HUGE_VAL) {
+		lp.lam = lp.phi = HUGE_VAL;
+		pj_errno = -15;
+	}
+	errno = pj_errno = 0;
+	xy.x = (xy.x * P->to_meter - P->x0) * P->ra; /* descale and de-offset */
+	xy.y = (xy.y * P->to_meter - P->y0) * P->ra;
+	lp = (*P->inv)(xy, P); /* inverse project */
+	if (pj_errno || (pj_errno = errno))
+		lp.lam = lp.phi = HUGE_VAL;
+	else {
+		lp.lam += P->lam0; /* reduce from del lp.lam */
+		if (!P->over)
+			lp.lam = adjlon(lp.lam); /* adjust longitude to CM */
+		if (P->geoc && fabs(fabs(lp.phi)-HALFPI) > EPS)
+			lp.phi = atan(P->one_es * tan(lp.phi));
+	}
+	return lp;
+}
-- 
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