From acc4e68a93b16832d397ff75bf5328a32094f525 Mon Sep 17 00:00:00 2001
From: mdroe <mdroe@stsci.edu>
Date: Tue, 5 Jun 2012 20:37:07 +0000
Subject: Fix bug with serial intersection where the intersection is null.

git-svn-id: http://svn.stsci.edu/svn/ssb/stsci_python/stsci_python/branches/sphere@17203 fe389314-cf27-0410-b35b-8c050e845b92

Former-commit-id: 18f248eb618623cad24c535ad787f818f5c76a09
---
 lib/polygon.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/polygon.py b/lib/polygon.py
index 689e272..4270ce6 100644
--- a/lib/polygon.py
+++ b/lib/polygon.py
@@ -631,6 +631,10 @@ class SphericalPolygon(object):
             result = copy(polygons[0])
             for polygon in polygons[1:]:
                 result = result.intersection(polygon)
+                # If we have a null intersection already, we don't
+                # need to go any further.
+                if len(result._points) < 3:
+                    return result
             return result
         else:
             raise ValueError("method must be 'parallel' or 'serial'")
-- 
cgit