<?xml version="1.0" encoding="UTF-8"?>
  <sect1 id="Operators">
	<title>Operators</title>
		<refentry id="geometry_overlaps">
		  <refnamediv>
			<refname>&amp;&amp;</refname>

			<refpurpose>Returns <varname>TRUE</varname> if A's 2D bounding box intersects B's 2D bounding box.</refpurpose>
		  </refnamediv>

		  <refsynopsisdiv>
			<funcsynopsis>
			  <funcprototype>
				<!-- TODO: Ideally, it would be nice if this could be reordered to
				"boolean (geometry A && geometry B)" instead of
				"boolean &&( geometry A, geometry B)" -->
				<funcdef>boolean <function>&amp;&amp;</function></funcdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>A</parameter>
				</paramdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>B</parameter>
				</paramdef>
			  </funcprototype>
			  <funcprototype>
				<funcdef>boolean <function>&amp;&amp;</function></funcdef>

				<paramdef>
				  <type>geography </type>

				  <parameter>A</parameter>
				</paramdef>

				<paramdef>
				  <type>geography </type>

				  <parameter>B</parameter>
				</paramdef>
			  </funcprototype>
			</funcsynopsis>
		  </refsynopsisdiv>

		  <refsection>
			<title>Description</title>

			<para>The <varname>&amp;&amp;</varname> operator returns <varname>TRUE</varname> if the 2D bounding box of geometry A intersects the 2D bounding box of geometry B.</para>

			<note><para>This operand will make use of any indexes that may be available on the
				geometries.</para></note>

			<para>Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.</para>
			<para>Availability: 1.5.0 support for geography was introduced.</para>
			<para>&curve_support;</para>
			<para>&P_support;</para>
		  </refsection>

		  <refsection>
			<title>Examples</title>

			<programlisting>SELECT tbl1.column1, tbl2.column1, tbl1.column2 &amp;&amp; tbl2.column2 AS overlaps
FROM ( VALUES
	(1, 'LINESTRING(0 0, 3 3)'::geometry),
	(2, 'LINESTRING(0 1, 0 5)'::geometry)) AS tbl1,
( VALUES
	(3, 'LINESTRING(1 2, 4 6)'::geometry)) AS tbl2;

 column1 | column1 | overlaps
---------+---------+----------
	   1 |       3 | t
	   2 |       3 | f
(2 rows)</programlisting>
<!-- TODO Add geography examples -->
		  </refsection>

		  <refsection>
			<title>See Also</title>

			<para>
				<xref linkend="ST_Geometry_Overabove" />,
				<xref linkend="ST_Geometry_Overright" />,
				<xref linkend="ST_Geometry_Overbelow" />,
				<xref linkend="ST_Geometry_Overleft" />,
				<xref linkend="ST_Geometry_Contain" />,
				<xref linkend="ST_Geometry_Contained" /></para>
		  </refsection>
		</refentry>
		
		<refentry id="geometry_overlaps_nd">
		  <refnamediv>
			<refname>&amp;&amp;&amp;</refname>

			<refpurpose>Returns <varname>TRUE</varname> if A's 3D bounding box intersects B's 3D bounding box.</refpurpose>
		  </refnamediv>

		  <refsynopsisdiv>
		      <funcsynopsis>
		      <funcprototype>
				<funcdef>boolean <function>&amp;&amp;&amp;</function></funcdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>A</parameter>
				</paramdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>B</parameter>
				</paramdef>
			  </funcprototype>
			</funcsynopsis>
		  </refsynopsisdiv>

		  <refsection>
			<title>Description</title>

			<para>The <varname>&amp;&amp;&amp;</varname> operator returns <varname>TRUE</varname> if the n-D bounding box of geometry A intersects the n-D bounding box of geometry B.</para>

			<note><para>This operand will make use of any indexes that may be available on the
				geometries.</para></note>

			<para>Availability: 2.0.0</para>
			<para>&curve_support;</para>
			<para>&P_support;</para>
			<para>&T_support;</para>
			<para>&Z_support;</para>
		  </refsection>

		  <refsection>
			<title>Examples: 3D LineStrings</title>

			<programlisting>SELECT tbl1.column1, tbl2.column1, tbl1.column2 &amp;&amp;&amp; tbl2.column2 AS overlaps_3d, 
			            tbl1.column2 &amp;&amp; tbl2.column2 AS overlaps_2d
FROM ( VALUES
	(1, 'LINESTRING Z(0 0 1, 3 3 2)'::geometry),
	(2, 'LINESTRING Z(1 2 0, 0 5 -1)'::geometry)) AS tbl1,
( VALUES
	(3, 'LINESTRING Z(1 2 1, 4 6 1)'::geometry)) AS tbl2;

 column1 | column1 | overlaps_3d | overlaps_2d
---------+---------+-------------+-------------
       1 |       3 | t           | t
       2 |       3 | f           | t
</programlisting>

		  </refsection>
		  <refsection>
			<title>Examples: 3M LineStrings</title>

			<programlisting>SELECT tbl1.column1, tbl2.column1, tbl1.column2 &amp;&amp;&amp; tbl2.column2 AS overlaps_3zm, 
			            tbl1.column2 &amp;&amp; tbl2.column2 AS overlaps_2d
FROM ( VALUES
	(1, 'LINESTRING M(0 0 1, 3 3 2)'::geometry),
	(2, 'LINESTRING M(1 2 0, 0 5 -1)'::geometry)) AS tbl1,
( VALUES
	(3, 'LINESTRING M(1 2 1, 4 6 1)'::geometry)) AS tbl2;

 column1 | column1 | overlaps_3zm | overlaps_2d
---------+---------+-------------+-------------
       1 |       3 | t           | t
       2 |       3 | f           | t
</programlisting>

		  </refsection>

		  <refsection>
			<title>See Also</title>

			<para><xref linkend="geometry_overlaps" /></para>
		  </refsection>
		</refentry>

		<refentry id="ST_Geometry_Overleft">
		  <refnamediv>
			<refname>&amp;&lt;</refname>

			<refpurpose>Returns <varname>TRUE</varname> if A's bounding box overlaps or is to the left of B's.</refpurpose>
		  </refnamediv>

		  <refsynopsisdiv>
			<funcsynopsis>
			  <funcprototype>
				<!-- TODO: Ideally, it would be nice if this could be reordered to
				"boolean (geometry A &< geometry B)" instead of
				"boolean &<( geometry A, geometry B)" -->
				<funcdef>boolean <function>&amp;&lt;</function></funcdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>A</parameter>
				</paramdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>B</parameter>
				</paramdef>
			  </funcprototype>
			</funcsynopsis>
		  </refsynopsisdiv>

		  <refsection>
			<title>Description</title>

			<para>The <varname>&amp;&lt;</varname> operator returns <varname>TRUE</varname> if the bounding box of geometry A
			overlaps or is to the left of the bounding box of geometry B, or more accurately, overlaps or is NOT to the right
			of the bounding box of geometry B.</para>

			<note><para>This operand will make use of any indexes that may be available on the
				geometries.</para></note>
		  </refsection>

		  <refsection>
			<title>Examples</title>

			<programlisting>SELECT tbl1.column1, tbl2.column1, tbl1.column2 &amp;&lt; tbl2.column2 AS overleft
FROM
  ( VALUES
	(1, 'LINESTRING(1 2, 4 6)'::geometry)) AS tbl1,
  ( VALUES
	(2, 'LINESTRING(0 0, 3 3)'::geometry),
	(3, 'LINESTRING(0 1, 0 5)'::geometry),
	(4, 'LINESTRING(6 0, 6 1)'::geometry)) AS tbl2;

 column1 | column1 | overleft
---------+---------+----------
	   1 |       2 | f
	   1 |       3 | f
	   1 |       4 | t
(3 rows)</programlisting>
		  </refsection>

		  <refsection>
			<title>See Also</title>

			<para>
				<xref linkend="geometry_overlaps" />,
				<xref linkend="ST_Geometry_Overabove" />,
				<xref linkend="ST_Geometry_Overright" />,
				<xref linkend="ST_Geometry_Overbelow" /></para>
		  </refsection>
		</refentry>

		<refentry id="ST_Geometry_Overbelow">
		  <refnamediv>
			<refname>&amp;&lt;|</refname>

			<refpurpose>Returns <varname>TRUE</varname> if A's bounding box overlaps or is below B's.</refpurpose>
		  </refnamediv>

		  <refsynopsisdiv>
			<funcsynopsis>
			  <funcprototype>
				<!-- TODO: Ideally, it would be nice if this could be reordered to
				"boolean (geometry A &<| geometry B)" instead of
				"boolean &<|( geometry A, geometry B)" -->
				<funcdef>boolean <function>&amp;&lt;|</function></funcdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>A</parameter>
				</paramdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>B</parameter>
				</paramdef>
			  </funcprototype>
			</funcsynopsis>
		  </refsynopsisdiv>

		  <refsection>
			<title>Description</title>

			<para>The <varname>&amp;&lt;|</varname> operator returns <varname>TRUE</varname> if the bounding box of geometry A
			overlaps or is below of the bounding box of geometry B, or more accurately, overlaps or is NOT above the bounding
			box of geometry B.</para>
			
			<para>&curve_support;</para>
			<para>&P_support;</para>

			<note><para>This operand will make use of any indexes that may be available on the
				geometries.</para></note>
		  </refsection>

		  <refsection>
			<title>Examples</title>

			<programlisting>SELECT tbl1.column1, tbl2.column1, tbl1.column2 &amp;&lt;| tbl2.column2 AS overbelow
FROM
  ( VALUES
	(1, 'LINESTRING(6 0, 6 4)'::geometry)) AS tbl1,
  ( VALUES
	(2, 'LINESTRING(0 0, 3 3)'::geometry),
	(3, 'LINESTRING(0 1, 0 5)'::geometry),
	(4, 'LINESTRING(1 2, 4 6)'::geometry)) AS tbl2;

 column1 | column1 | overbelow
---------+---------+-----------
	   1 |       2 | f
	   1 |       3 | t
	   1 |       4 | t
(3 rows)</programlisting>
		  </refsection>

		  <refsection>
			<title>See Also</title>

			<para>
				<xref linkend="geometry_overlaps" />,
				<xref linkend="ST_Geometry_Overabove" />,
				<xref linkend="ST_Geometry_Overright" />,
				<xref linkend="ST_Geometry_Overleft" /></para>
		  </refsection>
		</refentry>

		<refentry id="ST_Geometry_Overright">
		  <refnamediv>
			<refname>&amp;&gt;</refname>

			<refpurpose>Returns <varname>TRUE</varname> if A' bounding box overlaps or is to the right of B's.</refpurpose>
		  </refnamediv>

		  <refsynopsisdiv>
			<funcsynopsis>
			  <funcprototype>
				<!-- TODO: Ideally, it would be nice if this could be reordered to
				"boolean (geometry A &> geometry B)" instead of
				"boolean &>( geometry A, geometry B)" -->
				<funcdef>boolean <function>&amp;&gt;</function></funcdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>A</parameter>
				</paramdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>B</parameter>
				</paramdef>
			  </funcprototype>
			</funcsynopsis>
		  </refsynopsisdiv>

		  <refsection>
			<title>Description</title>

			<para>The <varname>&amp;&gt;</varname> operator returns <varname>TRUE</varname> if the bounding box of geometry A
			overlaps or is to the right of the bounding box of geometry B, or more accurately, overlaps or is NOT to the left
			of the bounding box of geometry B.</para>

			<note><para>This operand will make use of any indexes that may be available on the
				geometries.</para></note>
		  </refsection>

		  <refsection>
			<title>Examples</title>

			<programlisting>SELECT tbl1.column1, tbl2.column1, tbl1.column2 &amp;&gt; tbl2.column2 AS overright
FROM
  ( VALUES
	(1, 'LINESTRING(1 2, 4 6)'::geometry)) AS tbl1,
  ( VALUES
	(2, 'LINESTRING(0 0, 3 3)'::geometry),
	(3, 'LINESTRING(0 1, 0 5)'::geometry),
	(4, 'LINESTRING(6 0, 6 1)'::geometry)) AS tbl2;

 column1 | column1 | overright
---------+---------+-----------
	   1 |       2 | t
	   1 |       3 | t
	   1 |       4 | f
(3 rows)</programlisting>
		  </refsection>

		  <refsection>
			<title>See Also</title>

			<para>
				<xref linkend="geometry_overlaps" />,
				<xref linkend="ST_Geometry_Overabove" />,
				<xref linkend="ST_Geometry_Overbelow" />,
				<xref linkend="ST_Geometry_Overleft" /></para>
		  </refsection>
		</refentry>

		<refentry id="ST_Geometry_Left">
		  <refnamediv>
			<refname>&lt;&lt;</refname>

			<refpurpose>Returns <varname>TRUE</varname> if A's bounding box is strictly to the left of B's.</refpurpose>
		  </refnamediv>

		  <refsynopsisdiv>
			<funcsynopsis>
			  <funcprototype>
				<!-- TODO: Ideally, it would be nice if this could be reordered to
				"boolean (geometry A << geometry B)" instead of
				"boolean <<( geometry A, geometry B)" -->
				<funcdef>boolean <function>&lt;&lt;</function></funcdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>A</parameter>
				</paramdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>B</parameter>
				</paramdef>
			  </funcprototype>
			</funcsynopsis>
		  </refsynopsisdiv>

		  <refsection>
			<title>Description</title>

			<para>The <varname>&lt;&lt;</varname> operator returns <varname>TRUE</varname> if the bounding box of geometry A
			is strictly to the left of the bounding box of geometry B.</para>

			<note><para>This operand will make use of any indexes that may be available on the
				geometries.</para></note>
		  </refsection>

		  <refsection>
			<title>Examples</title>

			<programlisting>SELECT tbl1.column1, tbl2.column1, tbl1.column2 &lt;&lt; tbl2.column2 AS left
FROM
  ( VALUES
	(1, 'LINESTRING (1 2, 1 5)'::geometry)) AS tbl1,
  ( VALUES
	(2, 'LINESTRING (0 0, 4 3)'::geometry),
	(3, 'LINESTRING (6 0, 6 5)'::geometry),
	(4, 'LINESTRING (2 2, 5 6)'::geometry)) AS tbl2;

 column1 | column1 | left
---------+---------+------
	   1 |       2 | f
	   1 |       3 | t
	   1 |       4 | t
(3 rows)</programlisting>
		  </refsection>

		  <refsection>
			<title>See Also</title>

			<para><xref linkend="ST_Geometry_Right" />, <xref linkend="ST_Geometry_Above" />, <xref linkend="ST_Geometry_Below" /></para>
		  </refsection>
		</refentry>

		<refentry id="ST_Geometry_Below">
		  <refnamediv>
			<refname>&lt;&lt;|</refname>

			<refpurpose>Returns <varname>TRUE</varname> if A's bounding box is strictly below B's.</refpurpose>
		  </refnamediv>

		  <refsynopsisdiv>
			<funcsynopsis>
			  <funcprototype>
				<!-- TODO: Ideally, it would be nice if this could be reordered to
				"boolean (geometry A <<| geometry B)" instead of
				"boolean <<|( geometry A, geometry B)" -->
				<funcdef>boolean <function>&lt;&lt;|</function></funcdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>A</parameter>
				</paramdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>B</parameter>
				</paramdef>
			  </funcprototype>
			</funcsynopsis>
		  </refsynopsisdiv>

		  <refsection>
			<title>Description</title>

			<para>The <varname>&lt;&lt;|</varname> operator returns <varname>TRUE</varname> if the bounding box of geometry A
			is strictly below the bounding box of geometry B.</para>

			<note><para>This operand will make use of any indexes that may be available on the
				geometries.</para></note>
		  </refsection>

		  <refsection>
			<title>Examples</title>

			<programlisting>SELECT tbl1.column1, tbl2.column1, tbl1.column2 &lt;&lt;| tbl2.column2 AS below
FROM
  ( VALUES
	(1, 'LINESTRING (0 0, 4 3)'::geometry)) AS tbl1,
  ( VALUES
	(2, 'LINESTRING (1 4, 1 7)'::geometry),
	(3, 'LINESTRING (6 1, 6 5)'::geometry),
	(4, 'LINESTRING (2 3, 5 6)'::geometry)) AS tbl2;

 column1 | column1 | below
---------+---------+-------
	   1 |       2 | t
	   1 |       3 | f
	   1 |       4 | f
(3 rows)</programlisting>
		  </refsection>

		  <refsection>
			<title>See Also</title>

			<para><xref linkend="ST_Geometry_Left" />, <xref linkend="ST_Geometry_Right" />, <xref linkend="ST_Geometry_Above" /></para>
		  </refsection>
		</refentry>

		<refentry id="ST_Geometry_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>
				<!-- TODO: Ideally, it would be nice if this could be reordered to
				"boolean (geometry A = geometry B)" instead of
				"boolean =( geometry A, geometry B)" -->
				<funcdef>boolean <function>&#61;</function></funcdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>A</parameter>
				</paramdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>B</parameter>
				</paramdef>
			  </funcprototype>
			  
			  <funcprototype>
				<funcdef>boolean <function>&#61;</function></funcdef>
	
					<paramdef>
					  <type>geography </type>
	
					  <parameter>A</parameter>
					</paramdef>
	
					<paramdef>
					  <type>geography </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 geometry/geography A
			is the same as the bounding box of geometry/geography B.  PostgreSQL uses the =, &lt;, and &gt; operators defined for geometries to
			perform internal orderings and comparison of geometries (ie. in a GROUP BY or ORDER BY clause).</para>

			<warning>
			  <para>This is cause for a lot of confusion. When you compare geometryA =
			  geometryB it will return true even when the geometries are clearly
			  different IF their bounding boxes are the same. To check for true
			  equality use <xref linkend="ST_OrderingEquals" /> or <xref
			  linkend="ST_Equals" /></para>
			</warning>

			<caution><para>This operand will NOT make use of any indexes that may be available on the
				geometries.</para></caution>
				
			<para>&curve_support;</para>
			<para>&P_support;</para>
			<para>Changed:  2.0.0 , the bounding box of geometries was changed to use double precision instead of float4 precision of
			prior. The side effect of this is that in particular points in prior versions that were a little different may have returned
				true in prior versions and false in 2.0+ since their float4 boxes would be the same but there float8 (double precision), would be
				different.</para>

		  </refsection>

		  <refsection>
			<title>Examples</title>

			<programlisting>SELECT 'LINESTRING(0 0, 0 1, 1 0)'::geometry = 'LINESTRING(1 1, 0 0)'::geometry;
 ?column?
----------
 t
(1 row)

SELECT ST_AsText(column1)
FROM ( VALUES
	('LINESTRING(0 0, 1 1)'::geometry),
	('LINESTRING(1 1, 0 0)'::geometry)) AS foo;
	  st_astext
---------------------
 LINESTRING(0 0,1 1)
 LINESTRING(1 1,0 0)
(2 rows)

-- Note: the GROUP BY uses the "=" to compare for geometry equivalency.
SELECT ST_AsText(column1)
FROM ( VALUES
	('LINESTRING(0 0, 1 1)'::geometry),
	('LINESTRING(1 1, 0 0)'::geometry)) AS foo
GROUP BY column1;
	  st_astext
---------------------
 LINESTRING(0 0,1 1)
(1 row)

-- In versions prior to 2.0, this used to return true --
 SELECT ST_GeomFromText('POINT(1707296.37 4820536.77)') =
	ST_GeomFromText('POINT(1707296.27 4820536.87)') As pt_intersect;
	
--pt_intersect --
f
</programlisting>
		  </refsection>

		  <refsection>
			<title>See Also</title>

			<para><xref linkend="ST_Equals" />, <xref linkend="ST_OrderingEquals" />
			<!--, <xref linkend="ST_Geometry_LT" />, <xref linkend="ST_Geometry_GT" /> --></para>
		  </refsection>
		</refentry>

		<refentry id="ST_Geometry_Right">
		  <refnamediv>
			<refname>&gt;&gt;</refname>

			<refpurpose>Returns <varname>TRUE</varname> if A's bounding box is strictly to the right of B's.</refpurpose>
		  </refnamediv>

		  <refsynopsisdiv>
			<funcsynopsis>
			  <funcprototype>
				<!-- TODO: Ideally, it would be nice if this could be reordered to
				"boolean (geometry A >> geometry B)" instead of
				"boolean >>( geometry A, geometry B)" -->
				<funcdef>boolean <function>&gt;&gt;</function></funcdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>A</parameter>
				</paramdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>B</parameter>
				</paramdef>
			  </funcprototype>
			</funcsynopsis>
		  </refsynopsisdiv>

		  <refsection>
			<title>Description</title>

			<para>The <varname>&gt;&gt;</varname> operator returns <varname>TRUE</varname> if the bounding box of geometry A
			is strictly to the right of the bounding box of geometry B.</para>

			<note><para>This operand will make use of any indexes that may be available on the
				geometries.</para></note>
		  </refsection>

		  <refsection>
			<title>Examples</title>

			<programlisting>SELECT tbl1.column1, tbl2.column1, tbl1.column2 &gt;&gt; tbl2.column2 AS right
FROM
  ( VALUES
	(1, 'LINESTRING (2 3, 5 6)'::geometry)) AS tbl1,
  ( VALUES
	(2, 'LINESTRING (1 4, 1 7)'::geometry),
	(3, 'LINESTRING (6 1, 6 5)'::geometry),
	(4, 'LINESTRING (0 0, 4 3)'::geometry)) AS tbl2;

 column1 | column1 | right
---------+---------+-------
	   1 |       2 | t
	   1 |       3 | f
	   1 |       4 | f
(3 rows)</programlisting>
		  </refsection>

		  <refsection>
			<title>See Also</title>

			<para><xref linkend="ST_Geometry_Left" />, <xref linkend="ST_Geometry_Above" />, <xref linkend="ST_Geometry_Below" /></para>
		  </refsection>
		</refentry>

		<refentry id="ST_Geometry_Contained">
		  <refnamediv>
			<refname>@</refname>

			<refpurpose>Returns <varname>TRUE</varname> if A's bounding box is contained by B's.</refpurpose>
		  </refnamediv>

		  <refsynopsisdiv>
			<funcsynopsis>
			  <funcprototype>
				<!-- TODO: Ideally, it would be nice if this could be reordered to
				"boolean (geometry A @ geometry B)" instead of
				"boolean @( geometry A, geometry B)" -->
				<funcdef>boolean <function>@</function></funcdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>A</parameter>
				</paramdef>

				<paramdef>
				  <type>geometry </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 geometry A is completely
			contained by the bounding box of geometry B.</para>

			<note>
			  <para>This operand will make use of any indexes that may be available on the
			  geometries.</para>
			</note>
		  </refsection>

		  <refsection>
			<title>Examples</title>

			<programlisting>SELECT tbl1.column1, tbl2.column1, tbl1.column2 @ tbl2.column2 AS contained
FROM
  ( VALUES
	(1, 'LINESTRING (1 1, 3 3)'::geometry)) AS tbl1,
  ( VALUES
	(2, 'LINESTRING (0 0, 4 4)'::geometry),
	(3, 'LINESTRING (2 2, 4 4)'::geometry),
	(4, 'LINESTRING (1 1, 3 3)'::geometry)) AS tbl2;

 column1 | column1 | contained
---------+---------+-----------
	   1 |       2 | t
	   1 |       3 | f
	   1 |       4 | t
(3 rows)</programlisting>
		  </refsection>

		  <refsection>
			<title>See Also</title>

			<para><xref linkend="ST_Geometry_Contain" />, <xref linkend="geometry_overlaps" /></para>
		  </refsection>
		</refentry>

		<refentry id="ST_Geometry_Overabove">
		  <refnamediv>
			<refname>|&amp;&gt;</refname>

			<refpurpose>Returns <varname>TRUE</varname> if A's bounding box overlaps or is above B's.</refpurpose>
		  </refnamediv>

		  <refsynopsisdiv>
			<funcsynopsis>
			  <funcprototype>
				<!-- TODO: Ideally, it would be nice if this could be reordered to
				"boolean (geometry A |&> geometry B)" instead of
				"boolean |&>( geometry A, geometry B)" -->
				<funcdef>boolean <function>|&amp;&gt;</function></funcdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>A</parameter>
				</paramdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>B</parameter>
				</paramdef>
			  </funcprototype>
			</funcsynopsis>
		  </refsynopsisdiv>

		  <refsection>
			<title>Description</title>

			<para>The <varname>|&amp;&gt;</varname> operator returns <varname>TRUE</varname> if the bounding box of geometry A
			overlaps or is above the bounding box of geometry B, or more accurately, overlaps or is NOT below
			the bounding box of geometry B.</para>

			<note><para>This operand will make use of any indexes that may be available on the
			  geometries.</para></note>
		  </refsection>

		  <refsection>
			<title>Examples</title>

			<programlisting>SELECT tbl1.column1, tbl2.column1, tbl1.column2 |&amp;&gt; tbl2.column2 AS overabove
FROM
  ( VALUES
	(1, 'LINESTRING(6 0, 6 4)'::geometry)) AS tbl1,
  ( VALUES
	(2, 'LINESTRING(0 0, 3 3)'::geometry),
	(3, 'LINESTRING(0 1, 0 5)'::geometry),
	(4, 'LINESTRING(1 2, 4 6)'::geometry)) AS tbl2;

 column1 | column1 | overabove
---------+---------+-----------
	   1 |       2 | t
	   1 |       3 | f
	   1 |       4 | f
(3 rows)</programlisting>
		  </refsection>

		  <refsection>
			<title>See Also</title>

			<para>
				<xref linkend="geometry_overlaps" />,
				<xref linkend="ST_Geometry_Overright" />,
				<xref linkend="ST_Geometry_Overbelow" />,
				<xref linkend="ST_Geometry_Overleft" /></para>
		  </refsection>
		</refentry>

		<refentry id="ST_Geometry_Above">
		  <refnamediv>
			<refname>|&gt;&gt;</refname>

			<refpurpose>Returns <varname>TRUE</varname> if A's bounding box is strictly above B's.</refpurpose>
		  </refnamediv>

		  <refsynopsisdiv>
			<funcsynopsis>
			  <funcprototype>
				<!-- TODO: Ideally, it would be nice if this could be reordered to
				"boolean (geometry A |>> geometry B)" instead of
				"boolean |>>( geometry A, geometry B)" -->
				<funcdef>boolean <function>|&gt;&gt;</function></funcdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>A</parameter>
				</paramdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>B</parameter>
				</paramdef>
			  </funcprototype>
			</funcsynopsis>
		  </refsynopsisdiv>

		  <refsection>
			<title>Description</title>

			<para>The <varname>|&gt;&gt;</varname> operator returns <varname>TRUE</varname> if the bounding box of geometry A
			is strictly to the right of the bounding box of geometry B.</para>

			<note><para>This operand will make use of any indexes that may be available on the
			  geometries.</para></note>
		  </refsection>

		  <refsection>
			<title>Examples</title>

			<programlisting>SELECT tbl1.column1, tbl2.column1, tbl1.column2 |&gt;&gt; tbl2.column2 AS above
FROM
  ( VALUES
	(1, 'LINESTRING (1 4, 1 7)'::geometry)) AS tbl1,
  ( VALUES
	(2, 'LINESTRING (0 0, 4 2)'::geometry),
	(3, 'LINESTRING (6 1, 6 5)'::geometry),
	(4, 'LINESTRING (2 3, 5 6)'::geometry)) AS tbl2;

 column1 | column1 | above
---------+---------+-------
	   1 |       2 | t
	   1 |       3 | f
	   1 |       4 | f
(3 rows)</programlisting>
		  </refsection>

		  <refsection>
			<title>See Also</title>

			<para><xref linkend="ST_Geometry_Left" />, <xref linkend="ST_Geometry_Right" />, <xref linkend="ST_Geometry_Below" /></para>
		  </refsection>
		</refentry>

		<refentry id="ST_Geometry_Contain">
		  <refnamediv>
			<refname>~</refname>

			<refpurpose>Returns <varname>TRUE</varname> if A's bounding box contains B's.</refpurpose>
		  </refnamediv>

		  <refsynopsisdiv>
			<funcsynopsis>
			  <funcprototype>
				<!-- TODO: Ideally, it would be nice if this could be reordered to
				"boolean (geometry A ~ geometry B)" instead of
				"boolean ~( geometry A, geometry B)" -->
				<funcdef>boolean <function>~</function></funcdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>A</parameter>
				</paramdef>

				<paramdef>
				  <type>geometry </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 geometry A completely
			contains the bounding box of geometry B.</para>

			<note><para>This operand will make use of any indexes that may be available on the
			  geometries.</para></note>
		  </refsection>

		  <refsection>
			<title>Examples</title>

			<programlisting>SELECT tbl1.column1, tbl2.column1, tbl1.column2 ~ tbl2.column2 AS contains
FROM
  ( VALUES
	(1, 'LINESTRING (0 0, 3 3)'::geometry)) AS tbl1,
  ( VALUES
	(2, 'LINESTRING (0 0, 4 4)'::geometry),
	(3, 'LINESTRING (1 1, 2 2)'::geometry),
	(4, 'LINESTRING (0 0, 3 3)'::geometry)) AS tbl2;

 column1 | column1 | contains
---------+---------+----------
	   1 |       2 | f
	   1 |       3 | t
	   1 |       4 | t
(3 rows)</programlisting>
		  </refsection>

		  <refsection>
			<title>See Also</title>

			<para><xref linkend="ST_Geometry_Contained" />, <xref linkend="geometry_overlaps" /></para>
		  </refsection>
		</refentry>

		<refentry id="ST_Geometry_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>
				<!-- TODO: Ideally, it would be nice if this could be reordered to
				"boolean (geometry A ~= geometry B)" instead of
				"boolean ~=( geometry A, geometry B)" -->
				<funcdef>boolean <function>~=</function></funcdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>A</parameter>
				</paramdef>

				<paramdef>
				  <type>geometry </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 geometry/geography A
			is the same as the bounding box of geometry/geography B.</para>

			<note><para>This operand will make use of any indexes that may be available on the
			  geometries.</para></note>

			 <para>Availability: 1.5.0 changed behavior</para>
			 <para>&P_support;</para>

			<warning>
			  <para>This operator has changed behavior in PostGIS 1.5
			  from testing for actual geometric equality to only 
			  checking for bounding box equality. To complicate things 
			  it also depends on if you have done a hard or soft upgrade 
			  which behavior your database has. To find out which behavior
			  your database has you can run the query below.
				To check for true equality use <xref linkend="ST_OrderingEquals" /> or <xref
			  linkend="ST_Equals" /> and to check for bounding box equality <xref linkend="ST_Geometry_EQ" />; 
			  operator is a safer option.</para>
			  </warning>
		  </refsection>

		  <refsection>
			<title>Examples</title>
<programlisting>

select 'LINESTRING(0 0, 1 1)'::geometry ~= 'LINESTRING(0 1, 1 0)'::geometry as equality;
 equality   |
-----------------+
          t    |
 			</programlisting>
			<para>The above can be used to test if you have the new or old behavior of ~= operator.</para>
		  </refsection>
		  <refsection>
			<title>See Also</title>
			<para><xref linkend="ST_Equals" />, <xref linkend="ST_OrderingEquals" />, <xref linkend="ST_Geometry_EQ" /></para>
		  </refsection>
		</refentry>
		
		<refentry id="geometry_distance_centroid">
		  <refnamediv>
			<refname>&lt;-&gt;</refname>

			<refpurpose>Returns the distance between two points.  For point / point checks it uses floating point accuracy (as opposed to the double precision accuracy of the underlying point geometry).  For other geometry types
			the distance between the floating point bounding box centroids is returned.  Useful for doing distance ordering and nearest neighbor limits
			using KNN gist functionality.</refpurpose>
		  </refnamediv>

		  <refsynopsisdiv>
			<funcsynopsis>
			  <funcprototype>
				<funcdef>double precision <function>&lt;-&gt;</function></funcdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>A</parameter>
				</paramdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>B</parameter>
				</paramdef>
			  </funcprototype>
			</funcsynopsis>
		  </refsynopsisdiv>

		  <refsection>
			<title>Description</title>

			<para>The <varname>&lt;-&gt;</varname> operator returns distance between two points read from the spatial index for points (float precision).  For
			other geometries it returns the distance from centroid of bounding box of geometries.  Useful for doing nearest neighbor <emphasis role="strong">approximate</emphasis> distance ordering.</para>

			<note><para>This operand will make use of any indexes that may be available on the
			  geometries.  It is different from other operators that use spatial indexes in that the spatial index is only used when the operator
			  is in the ORDER BY clause.</para></note>
			<note><para>Index only kicks in if one of the geometries is a constant (not in a subquery/cte).  e.g. 'SRID=3005;POINT(1011102 450541)'::geometry instead of a.geom</para></note>
			<para>Refer to <ulink url="http://workshops.opengeo.org/postgis-intro/knn.html">OpenGeo workshop: Nearest-Neighbour Searching</ulink> for real live example.</para>

			 <para>Availability: 2.0.0 only available for PostgreSQL 9.1+</para>
			 	
		
		  </refsection>

		  <refsection>
			<title>Examples</title>
<programlisting><![CDATA[SELECT ST_Distance(geom, 'SRID=3005;POINT(1011102 450541)'::geometry) as d,edabbr, vaabbr 
FROM va2005 
ORDER BY d limit 10;]]>

        d         | edabbr | vaabbr
------------------+--------+--------
                0 | ALQ    | 128
 5541.57712511724 | ALQ    | 129A
 5579.67450712005 | ALQ    | 001
  6083.4207708641 | ALQ    | 131
  7691.2205404848 | ALQ    | 003
 7900.75451037313 | ALQ    | 122
 8694.20710669982 | ALQ    | 129B
 9564.24289057111 | ALQ    | 130
  12089.665931705 | ALQ    | 127
 18472.5531479404 | ALQ    | 002
(10 rows)
</programlisting>
<para>
Then the KNN raw answer:
</para>
<programlisting><![CDATA[SELECT st_distance(geom, 'SRID=3005;POINT(1011102 450541)'::geometry) as d,edabbr, vaabbr 
FROM va2005 
ORDER BY geom <-> 'SRID=3005;POINT(1011102 450541)'::geometry limit 10;]]>

        d         | edabbr | vaabbr
------------------+--------+--------
                0 | ALQ    | 128
 5579.67450712005 | ALQ    | 001
 5541.57712511724 | ALQ    | 129A
 8694.20710669982 | ALQ    | 129B
 9564.24289057111 | ALQ    | 130
  6083.4207708641 | ALQ    | 131
  12089.665931705 | ALQ    | 127
  24795.264503022 | ALQ    | 124
 24587.6584922302 | ALQ    | 123
 26764.2555463114 | ALQ    | 125
(10 rows)
</programlisting>
<para>
Note the misordering in the actual distances and the different entries that actually show up in the top 10.
</para>

<para>
Finally the hybrid:
</para>
<programlisting><![CDATA[WITH index_query AS (
  SELECT ST_Distance(geom, 'SRID=3005;POINT(1011102 450541)'::geometry) as d,edabbr, vaabbr
  	FROM va2005
  ORDER BY geom <-> 'SRID=3005;POINT(1011102 450541)'::geometry LIMIT 100) 
  SELECT * 
  	FROM index_query 
  ORDER BY d limit 10;]]>

        d         | edabbr | vaabbr
------------------+--------+--------
                0 | ALQ    | 128
 5541.57712511724 | ALQ    | 129A
 5579.67450712005 | ALQ    | 001
  6083.4207708641 | ALQ    | 131
  7691.2205404848 | ALQ    | 003
 7900.75451037313 | ALQ    | 122
 8694.20710669982 | ALQ    | 129B
 9564.24289057111 | ALQ    | 130
  12089.665931705 | ALQ    | 127
 18472.5531479404 | ALQ    | 002
(10 rows)

 			</programlisting>
		  </refsection>
		  <refsection>
			<title>See Also</title>
			<para><xref linkend="ST_DWithin" />, <xref linkend="ST_Distance" />, <xref linkend="geometry_distance_box" /></para>
		  </refsection>
		</refentry>
		
		<refentry id="geometry_distance_box">
		  <refnamediv>
			<refname>&lt;#&gt;</refname>

			<refpurpose>Returns the distance between bounding box of 2 geometries.  For point / point checks it's almost the same as distance (though may be different since the bounding box is at floating point accuracy and geometries are double precision).  Useful for doing distance ordering and nearest neighbor limits
			using KNN gist functionality.</refpurpose>
		  </refnamediv>

		  <refsynopsisdiv>
			<funcsynopsis>
			  <funcprototype>
				<funcdef>double precision <function>&lt;#&gt;</function></funcdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>A</parameter>
				</paramdef>

				<paramdef>
				  <type>geometry </type>

				  <parameter>B</parameter>
				</paramdef>
			  </funcprototype>
			</funcsynopsis>
		  </refsynopsisdiv>

		  <refsection>
			<title>Description</title>

			<para>The <varname>&lt;#&gt;</varname> KNN GIST operator returns distance between two floating point bounding boxes read from the spatial index if available.   Useful for doing nearest neighbor <emphasis role="strong">approximate</emphasis> distance ordering.</para>

			<note><para>This operand will make use of any indexes that may be available on the
			  geometries.  It is different from other operators that use spatial indexes in that the spatial index is only used when the operator
			  is in the ORDER BY clause.</para></note>
			<note><para>Index only kicks in if one of the geometries is a constant e.g. ORDER BY (ST_GeomFromText('POINT(1 2)') &lt;#&gt; geom)  instead of g1.geom &lt;#&gt;.</para></note>

			 <para>Availability: 2.0.0 only available for PostgreSQL 9.1+</para>
		
		  </refsection>

		  <refsection>
			<title>Examples</title>
<programlisting><![CDATA[SELECT *
FROM (
SELECT b.tlid, b.mtfcc, 
	b.geom <#> ST_GeomFromText('LINESTRING(746149 2948672,745954 2948576,
		745787 2948499,745740 2948468,745712 2948438,
		745690 2948384,745677 2948319)',2249) As b_dist, 
		ST_Distance(b.geom, ST_GeomFromText('LINESTRING(746149 2948672,745954 2948576,
		745787 2948499,745740 2948468,745712 2948438,
		745690 2948384,745677 2948319)',2249)) As act_dist
    FROM bos_roads As b 
    ORDER BY b_dist, b.tlid
    LIMIT 100) As foo
    ORDER BY act_dist, tlid LIMIT 10;]]>

   tlid    | mtfcc |      b_dist      |     act_dist
-----------+-------+------------------+------------------
  85732027 | S1400 |                0 |                0
  85732029 | S1400 |                0 |                0
  85732031 | S1400 |                0 |                0
  85734335 | S1400 |                0 |                0
  85736037 | S1400 |                0 |                0
 624683742 | S1400 |                0 | 128.528874268666
  85719343 | S1400 | 260.839270432962 | 260.839270432962
  85741826 | S1400 | 164.759294123275 | 260.839270432962
  85732032 | S1400 |           277.75 | 311.830282365264
  85735592 | S1400 |           222.25 | 311.830282365264
(10 rows)
</programlisting>
		  </refsection>
		  <refsection>
			<title>See Also</title>
			<para><xref linkend="ST_DWithin" />, <xref linkend="ST_Distance" />, <xref linkend="geometry_distance_centroid" /></para>
		  </refsection>
		</refentry>

	</sect1>