fix #2324

git-svn-id: http://svn.osgeo.org/qgis/trunk@13724 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: jef

src/core/qgsdistancearea.cpp

@@ -178,6 +178,9 @@ double QgsDistanceArea::measure( QgsGeometry* geometry )
     return 0.0;
 
   unsigned char* wkb = geometry->asWkb();
+  if ( !wkb )
+    return 0.0;
+
   unsigned char* ptr;
   unsigned int wkbType;
   double res, resTotal = 0;