update ExteriorRing doc

git-svn-id: http://svn.osgeo.org/postgis/trunk@1214 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/doc/postgis.xml b/doc/postgis.xml
index 7f86fa6476731b7c73612ca445f29e6e28b11bc9..9b34ce5d27e2cf861da14743f02a450b56bfeb45 100644 (file)
--- a/doc/postgis.xml
+++ b/doc/postgis.xml
@@ -3049,9 +3049,8 @@ dimension
             <term>ExteriorRing(geometry)</term>
 
             <listitem>
-              <para>Return the exterior ring of the first polygon in the
-              geometry. Return NULL if there is no polygon in the
-              geometry.</para>
+              <para>Return the exterior ring of the polygon geometry.
+             Return NULL if the geometry is not a polygon.</para>
             </listitem>
           </varlistentry>