#2541 document = and ~= raster operators

git-svn-id: http://svn.osgeo.org/postgis/trunk@12120 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/doc/reference_raster.xml b/doc/reference_raster.xml
index f6d4a018da0643a8f862d7855fd53d911476b544..cebba247ea87c8d8fbf1d6ce18cd881d7bb94ce4 100644 (file)
--- a/doc/reference_raster.xml
+++ b/doc/reference_raster.xml
@@ -12393,6 +12393,107 @@ a_rid | b_rid | overleft
 </programlisting>
                  </refsection>
                 </refentry>
+                
+               <refentry id="RT_Raster_EQ">
+                 <refnamediv>
+                       <refname>&#61;</refname>
+
+                       <refpurpose>Returns <varname>TRUE</varname> if A's bounding box is the same as B's. Uses double precision bounding box.</refpurpose>
+                 </refnamediv>
+
+                 <refsynopsisdiv>
+                       <funcsynopsis>
+                         <funcprototype>
+                               <funcdef>boolean <function>&#61;</function></funcdef>
+
+                               <paramdef>
+                                 <type>raster </type>
+
+                                 <parameter>A</parameter>
+                               </paramdef>
+
+                               <paramdef>
+                                 <type>raster </type>
+
+                                 <parameter>B</parameter>
+                               </paramdef>
+                         </funcprototype>
+                       </funcsynopsis>
+                 </refsynopsisdiv>
+
+                 <refsection>
+                       <title>Description</title>
+
+                       <para>The <varname>&#61;</varname> operator returns <varname>TRUE</varname> if the bounding box of raster A
+                       is the same as the bounding box of raster B.  PostgreSQL uses the =, &lt;, and &gt; operators defined for rasters  to
+                       perform internal orderings and comparison of rasters (ie. in a GROUP BY or ORDER BY clause).</para>
+
+                       <caution><para>This operand will NOT make use of any indexes that may be available on the
+                               rasters. Use <xref linkend="RT_Raster_Same" /> instead.  This operator exists mostly so one can group by the raster column.</para></caution>
+                               
+                       <para>Availability:  2.1.0 </para>
+
+                 </refsection>
+
+                 <refsection>
+                       <title>See Also</title>
+
+                       <para><xref linkend="RT_Raster_Same" /></para>
+                 </refsection>
+               </refentry>
+                
+               <refentry id="RT_Raster_Same">
+                 <refnamediv>
+                       <refname>~=</refname>
+
+                       <refpurpose>Returns <varname>TRUE</varname> if A's bounding box is the same as B's.</refpurpose>
+                 </refnamediv>
+
+                 <refsynopsisdiv>
+                       <funcsynopsis>
+                         <funcprototype>
+                               <funcdef>boolean <function>~=</function></funcdef>
+
+                               <paramdef>
+                                 <type>raster </type>
+
+                                 <parameter>A</parameter>
+                               </paramdef>
+
+                               <paramdef>
+                                 <type>raster </type>
+
+                                 <parameter>B</parameter>
+                               </paramdef>
+                         </funcprototype>
+                       </funcsynopsis>
+                 </refsynopsisdiv>
+
+                 <refsection>
+                       <title>Description</title>
+
+                       <para>The <varname>~=</varname> operator returns <varname>TRUE</varname> if the bounding box of raster A
+                       is the same as the bounding box of raster B.</para>
+
+                       <note><para>This operand will make use of any indexes that may be available on the
+                         rasters.</para></note>
+
+                        <para>Availability: 2.0.0</para>
+
+                 </refsection>
+
+                 <refsection>
+                       <title>Examples</title>
+                       <para>Very useful usecase is for taking two sets of single band rasters that are of the same chunk but represent different themes and creating a multi-band raster
+<programlisting>SELECT ST_AddBand(prec.rast, alt.rast) As new_rast
+  FROM prec INNER JOIN alt ON (prec.rast ~= alt.rast);
+                       </programlisting>
+                 </refsection>
+                 <refsection>
+                       <title>See Also</title>
+                       <para><xref linkend="RT_ST_AddBand" />, <xref linkend="RT_Raster_EQ" /></para>
+                 </refsection>
+               </refentry>
        </sect1>
        
        <sect1 id="Raster_Relationships">