SF.net SVN: matplotlib:[8868] trunk/toolkits/basemap/src/PJ_hammer.c

[<js...@us...>]

Revision: 8868
          http://matplotlib.svn.sourceforge.net/matplotlib/?rev=8868&view=rev
Author:   jswhit
Date:     2010-12-30 16:14:19 +0000 (Thu, 30 Dec 2010)

Log Message:
-----------
detect projection out of range, set error flag.

Modified Paths:
--------------
    trunk/toolkits/basemap/src/PJ_hammer.c

Modified: trunk/toolkits/basemap/src/PJ_hammer.c
===================================================================
--- trunk/toolkits/basemap/src/PJ_hammer.c	2010-12-30 13:09:06 UTC (rev 8867)
+++ trunk/toolkits/basemap/src/PJ_hammer.c	2010-12-30 16:14:19 UTC (rev 8868)
@@ -2,6 +2,7 @@
 	double w; \
 	double m, rm;
 #define PJ_LIB__
+# define EPS 1.0e-10
 # include	<projects.h>
 PROJ_HEAD(hammer, "Hammer & Eckert-Greifendorff")
 	"\n\tMisc Sph, \n\tW= M=";
@@ -15,9 +16,15 @@
 }
 INVERSE(s_inverse); /* spheroid */
         double z;
-	z = sqrt(1. - (0.5 * P->w * xy.x) * (0.5 * P->w * xy.x) - (0.5 * xy.y) * (0.5 * xy.y));
-	lp.lam = aatan2(P->w * xy.x * z,2. * z * z - 1)/P->w;
-	lp.phi = aasin(z * xy.y);
+	z = sqrt(1. - 0.25*P->w*P->w*xy.x*xy.x - 0.25*xy.y*xy.y);
+	if (fabs(2.*z*z-1.) < EPS) {
+           lp.lam = HUGE_VAL;
+           lp.phi = HUGE_VAL;
+           pj_errno = -14;
+	} else {
+	   lp.lam = aatan2(P->w * xy.x * z,2. * z * z - 1)/P->w;
+	   lp.phi = aasin(z * xy.y);
+        }
 	return (lp);
 }
 FREEUP; if (P) pj_dalloc(P); }


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