<?xml version="1.0" encoding="UTF-8"?>
  <sect1 id="BBox_Functions">
	  <sect1info>
	    <abstract>
			<para>These functions produce or operate on bounding boxes.
			They can also provide and accept geometry values, by using automatic or explicit casts.
			</para>
			<para>See also <xref linkend="PostGIS_BoxFunctions" />.</para>
    	</abstract>
    </sect1info>

	<title>Bounding Box Functions</title>

	<refentry id="Box2D">
	  <refnamediv>
		<refname>Box2D</refname>

		<refpurpose>Returns a BOX2D representing the 2D extent of a geometry.</refpurpose>
	  </refnamediv>

	  <refsynopsisdiv>
		<funcsynopsis>
		  <funcprototype>
			<funcdef>box2d <function>Box2D</function></funcdef>
			<paramdef><type>geometry </type> <parameter>geom</parameter></paramdef>
		  </funcprototype>
		</funcsynopsis>
	  </refsynopsisdiv>

	  <refsection>
		<title>Description</title>

		<para>Returns a <xref linkend="box2d_type" /> representing the 2D extent of the geometry.</para>

		<para>Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.</para>
		<para>&curve_support;</para>
		<para>&P_support;</para>
		<para>&T_support;</para>
	  </refsection>

	  <refsection>
		<title>Examples</title>

<programlisting>SELECT Box2D(ST_GeomFromText('LINESTRING(1 2, 3 4, 5 6)'));

box2d
---------
BOX(1 2,5 6)
</programlisting>
<programlisting>
SELECT Box2D(ST_GeomFromText('CIRCULARSTRING(220268 150415,220227 150505,220227 150406)'));

box2d
--------
BOX(220186.984375 150406,220288.25 150506.140625)
</programlisting>
	  </refsection>

	  <!-- Optionally add a "See Also" section -->
	  <refsection>
		<title>See Also</title>

		<para><xref linkend="Box3D" />, <xref linkend="ST_GeomFromText" /></para>
	  </refsection>
	</refentry>

	<refentry id="Box3D">
	  <refnamediv>
		<refname>Box3D</refname>

		<refpurpose>Returns a BOX3D representing the 3D extent of a geometry.</refpurpose>
	  </refnamediv>

	  <refsynopsisdiv>
		<funcsynopsis>
		  <funcprototype>
			<funcdef>box3d <function>Box3D</function></funcdef>
			<paramdef><type>geometry </type> <parameter>geom</parameter></paramdef>
		  </funcprototype>
		</funcsynopsis>
	  </refsynopsisdiv>

	  <refsection>
		<title>Description</title>

		<para>Returns a <xref linkend="box3d_type" /> representing the 3D extent of the geometry.</para>
		<para>Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.</para>
		<para>&curve_support;</para>
		<para>&P_support;</para>
		<para>&T_support;</para>
		<para>&Z_support;</para>
	  </refsection>


	  <refsection>
		<title>Examples</title>

<programlisting>SELECT Box3D(ST_GeomFromEWKT('LINESTRING(1 2 3, 3 4 5, 5 6 5)'));

Box3d
---------
BOX3D(1 2 3,5 6 5)
</programlisting>
<programlisting>
SELECT Box3D(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 1,220227 150406 1)'));

Box3d
--------
BOX3D(220227 150406 1,220268 150415 1)
</programlisting>
	  </refsection>

	  <!-- Optionally add a "See Also" section -->
	  <refsection>
		<title>See Also</title>

		<para><xref linkend="Box2D" />, <xref linkend="ST_GeomFromEWKT" /></para>
	  </refsection>
	</refentry>

	<refentry id="ST_EstimatedExtent">
	  <refnamediv>
		<refname>ST_EstimatedExtent</refname>

		<refpurpose>Returns the estimated extent of a spatial table.</refpurpose>
	  </refnamediv>

	  <refsynopsisdiv>
		<funcsynopsis>
		  <funcprototype>
			<funcdef>box2d <function>ST_EstimatedExtent</function></funcdef>
			<paramdef><type>text </type> <parameter>schema_name</parameter></paramdef>
			<paramdef><type>text </type> <parameter>table_name</parameter></paramdef>
			<paramdef><type>text </type> <parameter>geocolumn_name</parameter></paramdef>
			<paramdef><type>boolean </type> <parameter>parent_only</parameter></paramdef>
		  </funcprototype>


		  <funcprototype>
			<funcdef>box2d <function>ST_EstimatedExtent</function></funcdef>
			<paramdef><type>text </type> <parameter>schema_name</parameter></paramdef>
			<paramdef><type>text </type> <parameter>table_name</parameter></paramdef>
			<paramdef><type>text </type> <parameter>geocolumn_name</parameter></paramdef>
		  </funcprototype>

		  <funcprototype>
			<funcdef>box2d <function>ST_EstimatedExtent</function></funcdef>
			<paramdef><type>text </type> <parameter>table_name</parameter></paramdef>
			<paramdef><type>text </type> <parameter>geocolumn_name</parameter></paramdef>
		  </funcprototype>
		</funcsynopsis>
	  </refsynopsisdiv>

	  <refsection>
		<title>Description</title>

		<para>Returns the estimated extent of a spatial table as a <xref linkend="box2d_type" />.
            The	current schema is used if not specified.
			The estimated extent is taken from the geometry column's statistics.
            This is usually much faster than computing the exact extent of the table
            using <xref linkend="ST_Extent" /> or <xref linkend="ST_3DExtent" />.
            </para>
        <para>
            The default behavior is to also use statistics collected from child tables (tables
			with INHERITS) if available. If <varname>parent_only</varname> is set to TRUE, only
			statistics for the given table are used and child tables are ignored.
		</para>

		<para>For PostgreSQL &gt;= 8.0.0 statistics are gathered by VACUUM
		ANALYZE and the result extent will be about 95% of the actual one.
        For PostgreSQL &lt; 8.0.0 statistics are gathered by running
		<code>update_geometry_stats()</code> and the result extent is exact.
        </para>

        <note>
            <para>
            In the absence of statistics (empty table or no ANALYZE called) this function
            returns NULL.  Prior to version 1.5.4 an exception was thrown instead.
		    </para>
        </note>

    <para>Availability: 1.0.0</para>
    <para>Changed: 2.1.0. Up to 2.0.x this was called ST_Estimated_Extent.</para>

		<para>&curve_support;</para>
	  </refsection>


	  <refsection>
		<title>Examples</title>

		<programlisting>SELECT ST_EstimatedExtent('ny', 'edges', 'geom');
--result--
BOX(-8877653 4912316,-8010225.5 5589284)

SELECT ST_EstimatedExtent('feature_poly', 'geom');
--result--
BOX(-124.659652709961 24.6830825805664,-67.7798080444336 49.0012092590332)
		</programlisting>
	  </refsection>

	  <!-- Optionally add a "See Also" section -->
	  <refsection>
		<title>See Also</title>

		<para><xref linkend="ST_Extent" />, <xref linkend="ST_3DExtent" /></para>
	  </refsection>
	</refentry>

	<refentry id="ST_Expand">
	  <refnamediv>
		<refname>ST_Expand</refname>
		<refpurpose>Returns a bounding box expanded from another bounding box or a geometry.</refpurpose>
	  </refnamediv>

	  <refsynopsisdiv>
		<funcsynopsis>
		  <funcprototype>
			<funcdef>geometry <function>ST_Expand</function></funcdef>
			<paramdef><type>geometry </type> <parameter>geom</parameter></paramdef>
			<paramdef><type>float</type> <parameter>units_to_expand</parameter></paramdef>
		  </funcprototype>

		  <funcprototype>
			<funcdef>geometry <function>ST_Expand</function></funcdef>
			<paramdef><type>geometry </type> <parameter>geom</parameter></paramdef>
			<paramdef><type>float</type> <parameter>dx</parameter></paramdef>
			<paramdef><type>float</type> <parameter>dy</parameter></paramdef>
			<paramdef choice="opt"><type>float</type> <parameter>dz=0</parameter></paramdef>
			<paramdef choice="opt"><type>float</type> <parameter>dm=0</parameter></paramdef>
		  </funcprototype>

		  <funcprototype>
			<funcdef>box2d <function>ST_Expand</function></funcdef>
			<paramdef><type>box2d </type> <parameter>box</parameter></paramdef>
			<paramdef><type>float</type> <parameter>units_to_expand</parameter></paramdef>
		  </funcprototype>

		  <funcprototype>
			<funcdef>box2d <function>ST_Expand</function></funcdef>
			<paramdef><type>box2d </type> <parameter>box</parameter></paramdef>
			<paramdef><type>float</type> <parameter>dx</parameter></paramdef>
			<paramdef><type>float</type> <parameter>dy</parameter></paramdef>
		  </funcprototype>

		  <funcprototype>
			<funcdef>box3d <function>ST_Expand</function></funcdef>
			<paramdef><type>box3d </type> <parameter>box</parameter></paramdef>
			<paramdef><type>float</type> <parameter>units_to_expand</parameter></paramdef>
		  </funcprototype>

		  <funcprototype>
			<funcdef>box3d <function>ST_Expand</function></funcdef>
			<paramdef><type>box3d </type> <parameter>box</parameter></paramdef>
			<paramdef><type>float</type>  <parameter>dx</parameter></paramdef>
			<paramdef><type>float</type>  <parameter>dy</parameter></paramdef>
			<paramdef choice="opt"><type>float</type>  <parameter>dz=0</parameter></paramdef>
		  </funcprototype>
		</funcsynopsis>
	  </refsynopsisdiv>

	  <refsection>
		<title>Description</title>

		<para>Returns a bounding box expanded from the bounding box of the input,
			either by specifying a single distance with which the box should be expanded on both
			axes, or by specifying an expansion distance for each axis.

			Uses double-precision. Can be used for distance queries, or to add a bounding box
			filter to a query to take advantage of a spatial index.</para>

		<para>In addition to the version of ST_Expand accepting and returning a geometry, variants
			are provided that accept and return
            <xref linkend="box2d_type" /> and <xref linkend="box3d_type" /> data types.
		</para>

		<para>Distances are in the units of the spatial reference system of the input.</para>

		<para>ST_Expand is similar to <xref linkend="ST_Buffer" />,
			except while buffering expands a geometry in all directions,
			ST_Expand expands the bounding box along each axis.</para>

		<note>
		  <para>Pre version 1.3, ST_Expand was used in conjunction with <xref linkend="ST_Distance" /> to do indexable distance queries.  For example,
			<code>geom &amp;&amp; ST_Expand('POINT(10 20)', 10) AND ST_Distance(geom, 'POINT(10 20)') &lt; 10</code>.
			This has been replaced by the simpler and more efficient <xref linkend="ST_DWithin" /> function.</para>
		</note>

        <para>Availability: 1.5.0 behavior changed to output double precision instead of float4 coordinates.</para>
        <para>Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.</para>
        <para>Enhanced: 2.3.0 support was added to expand a box by different amounts in different dimensions.</para>

		<para>&P_support;</para>
		<para>&T_support;</para>

	  </refsection>

	  <refsection>
		<title>Examples</title>
		<note><para>Examples below use US National Atlas Equal Area (SRID=2163) which is a meter projection</para></note>
		<programlisting>
		<!-- TODO: fix results of documentation to reflect new behavior -->
--10 meter expanded box around bbox of a linestring
SELECT CAST(ST_Expand(ST_GeomFromText('LINESTRING(2312980 110676,2312923 110701,2312892 110714)', 2163),10) As box2d);
					 st_expand
------------------------------------
 BOX(2312882 110666,2312990 110724)

--10 meter expanded 3D box of a 3D box
SELECT ST_Expand(CAST('BOX3D(778783 2951741 1,794875 2970042.61545891 10)' As box3d),10)
							  st_expand
-----------------------------------------------------
 BOX3D(778773 2951731 -9,794885 2970052.61545891 20)

 --10 meter geometry astext rep of a expand box around a point geometry
 SELECT ST_AsEWKT(ST_Expand(ST_GeomFromEWKT('SRID=2163;POINT(2312980 110676)'),10));
											st_asewkt
-------------------------------------------------------------------------------------------------
 SRID=2163;POLYGON((2312970 110666,2312970 110686,2312990 110686,2312990 110666,2312970 110666))

		</programlisting>
	  </refsection>

	  <refsection>
		<title>See Also</title>
		<para><xref linkend="ST_Buffer" />, <xref linkend="ST_DWithin" />, <xref linkend="ST_SRID" /></para>
	  </refsection>
	</refentry>

	<refentry id="ST_Extent">
	  <refnamediv>
		<refname>ST_Extent</refname>
		<refpurpose>Aggregate function that returns the bounding box of geometries.</refpurpose>
	  </refnamediv>

	  <refsynopsisdiv>
		<funcsynopsis>
		  <funcprototype>
			<funcdef>box2d <function>ST_Extent</function></funcdef>
			<paramdef><type>geometry set</type> <parameter>geomfield</parameter></paramdef>
		  </funcprototype>
		</funcsynopsis>
	  </refsynopsisdiv>

	  <refsection>
		<title>Description</title>

		<para>An aggregate function that returns a <xref linkend="box2d_type" /> bounding box
        that bounds a set of geometries.
        </para>

		<para>The bounding box coordinates are in the spatial reference system of the input geometries.</para>

		<para>ST_Extent is similar in concept to Oracle Spatial/Locator's SDO_AGGR_MBR.</para>

		<note>
		  <para>ST_Extent returns boxes with only X and Y ordinates even with 3D geometries.
          To return XYZ ordinates use <xref linkend="ST_3DExtent" />.</para>
		</note>

		<note>
		  <para>The returned <code>box3d</code> value does not include a SRID.
            Use <xref linkend="ST_SetSRID" /> to convert it into a geometry with SRID metadata.
            The SRID is the same as the input geometries.</para>
		</note>

		<para>Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.</para>
		<para>&P_support;</para>
		<para>&T_support;</para>

	  </refsection>

	  <refsection>
		<title>Examples</title>
		<note><para>Examples below use Massachusetts State Plane ft (SRID=2249)</para></note>
		<programlisting>

SELECT ST_Extent(geom) as bextent FROM sometable;
					 st_bextent
------------------------------------
BOX(739651.875 2908247.25,794875.8125 2970042.75)


--Return extent of each category of geometries
SELECT ST_Extent(geom) as bextent
FROM sometable
GROUP BY category ORDER BY category;

					  bextent                       |         name
----------------------------------------------------+----------------
 BOX(778783.5625 2951741.25,794875.8125 2970042.75) | A
 BOX(751315.8125 2919164.75,765202.6875 2935417.25) | B
 BOX(739651.875 2917394.75,756688.375 2935866)      | C

 --Force back into a geometry
 -- and render the extended text representation of that geometry
SELECT ST_SetSRID(ST_Extent(geom),2249) as bextent FROM sometable;

				bextent
--------------------------------------------------------------------------------
 SRID=2249;POLYGON((739651.875 2908247.25,739651.875 2970042.75,794875.8125 2970042.75,
 794875.8125 2908247.25,739651.875 2908247.25))
		</programlisting>
	  </refsection>

	  <refsection>
		<title>See Also</title>
		<para>
            <xref linkend="ST_EstimatedExtent" />,
            <xref linkend="ST_3DExtent" />,
            <xref linkend="ST_SetSRID" />
		</para>
	  </refsection>
	</refentry>

	<refentry id="ST_3DExtent">
	  <refnamediv>
		<refname>ST_3DExtent</refname>
		<refpurpose>Aggregate function that returns the 3D bounding box of geometries.</refpurpose>
	  </refnamediv>

	  <refsynopsisdiv>
		<funcsynopsis>
		  <funcprototype>
			<funcdef>box3d <function>ST_3DExtent</function></funcdef>
			<paramdef><type>geometry set</type> <parameter>geomfield</parameter></paramdef>
		  </funcprototype>
		</funcsynopsis>
	  </refsynopsisdiv>

	  <refsection>
		<title>Description</title>

		<para>An aggregate function that returns a <xref linkend="box3d_type" /> (includes Z ordinate) bounding box
        that bounds a set of geometries.
        </para>
		<para>The bounding box coordinates are in the spatial reference system of the input geometries.</para>

		<note>
		  <para>The returned <code>box3d</code> value does not include a SRID.
            Use <xref linkend="ST_SetSRID" /> to convert it into a geometry with SRID metadata.
            The SRID is the same as the input geometries.</para>
		</note>

		<para>Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.</para>
		<para>Changed: 2.0.0 In prior versions this used to be called ST_Extent3D</para>
		<para>&Z_support;</para>
		<para>&curve_support;</para>
		<para>&P_support;</para>
		<para>&T_support;</para>
	  </refsection>

	  <refsection>
		<title>Examples</title>
		<programlisting>
SELECT ST_3DExtent(foo.geom) As b3extent
FROM (SELECT ST_MakePoint(x,y,z) As geom
	FROM generate_series(1,3) As x
		CROSS JOIN generate_series(1,2) As y
		CROSS JOIN generate_series(0,2) As Z) As foo;
	  b3extent
--------------------
 BOX3D(1 1 0,3 2 2)

--Get the extent of various elevated circular strings
SELECT ST_3DExtent(foo.geom) As b3extent
FROM (SELECT ST_Translate(ST_Force_3DZ(ST_LineToCurve(ST_Buffer(ST_Point(x,y),1))),0,0,z) As geom
	FROM generate_series(1,3) As x
		CROSS JOIN generate_series(1,2) As y
		CROSS JOIN generate_series(0,2) As Z) As foo;

	b3extent
--------------------
 BOX3D(1 0 0,4 2 2)
		</programlisting>
	  </refsection>

	  <refsection>
		<title>See Also</title>
		<para><xref linkend="ST_Extent" />, <xref linkend="ST_Force_3DZ" />, <xref linkend="ST_SetSRID" /></para>
	  </refsection>
	</refentry>

	<refentry id="ST_MakeBox2D">
	  <refnamediv>
		<refname>ST_MakeBox2D</refname>

		<refpurpose>Creates a BOX2D defined by two 2D point geometries.</refpurpose>
	  </refnamediv>

	  <refsynopsisdiv>
		<funcsynopsis>
		  <funcprototype>
			<funcdef>box2d <function>ST_MakeBox2D</function></funcdef>
			<paramdef><type>geometry </type> <parameter>pointLowLeft</parameter></paramdef>
			<paramdef><type>geometry </type> <parameter>pointUpRight</parameter></paramdef>
		  </funcprototype>
		</funcsynopsis>
	  </refsynopsisdiv>

	  <refsection>
		<title>Description</title>

		<para>Creates a <xref linkend="box2d_type" /> defined by two Point
			geometries.  This is useful for doing range queries.</para>
	  </refsection>


	  <refsection>
		<title>Examples</title>

		<programlisting>
--Return all features that fall reside or partly reside in a US national atlas coordinate bounding box
--It is assumed here that the geometries are stored with SRID = 2163 (US National atlas equal area)
SELECT feature_id, feature_name, geom
FROM features
WHERE geom &amp;&amp; ST_SetSRID(ST_MakeBox2D(ST_Point(-989502.1875, 528439.5625),
	ST_Point(-987121.375 ,529933.1875)),2163)</programlisting>
	  </refsection>

	  <!-- Optionally add a "See Also" section -->
	  <refsection>
		<title>See Also</title>

		<para><xref linkend="ST_Point" />, <xref linkend="ST_SetSRID" />, <xref linkend="ST_SRID" /></para>
	  </refsection>
	</refentry>

	<refentry id="ST_3DMakeBox">
	  <refnamediv>
		<refname>ST_3DMakeBox</refname>

		<refpurpose>Creates a BOX3D defined by two 3D point	geometries.</refpurpose>
	  </refnamediv>
	  <refsynopsisdiv>
		<funcsynopsis>
		  <funcprototype>
			<funcdef>box3d <function>ST_3DMakeBox</function></funcdef>
			<paramdef><type>geometry </type> <parameter>point3DLowLeftBottom</parameter></paramdef>
			<paramdef><type>geometry </type> <parameter>point3DUpRightTop</parameter></paramdef>
		  </funcprototype>
		</funcsynopsis>
	  </refsynopsisdiv>

	  <refsection>
		<title>Description</title>

		<para>Creates a <xref linkend="box3d_type" /> defined by two 3D Point
			geometries. </para>

		<!-- Optionally mention 3D support -->
		<para><inlinemediaobject>
			<imageobject>
			  <imagedata fileref="images/check.png" />
			</imageobject>
		  </inlinemediaobject> This function supports 3D and will not drop the z-index.</para>
		 <para>Changed: 2.0.0 In prior versions this used to be called ST_MakeBox3D</para>
	  </refsection>


	  <refsection>
		<title>Examples</title>

		<programlisting>
SELECT ST_3DMakeBox(ST_MakePoint(-989502.1875, 528439.5625, 10),
	ST_MakePoint(-987121.375 ,529933.1875, 10)) As abb3d

--bb3d--
--------
BOX3D(-989502.1875 528439.5625 10,-987121.375 529933.1875 10)
	</programlisting>
	  </refsection>

	  <!-- Optionally add a "See Also" section -->
	  <refsection>
		<title>See Also</title>

		<para><xref linkend="ST_MakePoint" />, <xref linkend="ST_SetSRID" />, <xref linkend="ST_SRID" /></para>
	  </refsection>
	</refentry>

		<refentry id="ST_XMax">
	  <refnamediv>
		<refname>ST_XMax</refname>

		<refpurpose>Returns the X maxima of a 2D or 3D bounding box or a geometry.</refpurpose>
	  </refnamediv>

	  <refsynopsisdiv>
		<funcsynopsis>
		  <funcprototype>
			<funcdef>float <function>ST_XMax</function></funcdef>
			<paramdef><type>box3d </type> <parameter>aGeomorBox2DorBox3D</parameter></paramdef>
		  </funcprototype>
		</funcsynopsis>
	  </refsynopsisdiv>

	  <refsection>
		<title>Description</title>

		<para>Returns the X maxima of a 2D or 3D bounding box or a geometry.</para>

		<note>
		  <para>Although this function is only defined for box3d, it also works for box2d and geometry values due to automatic casting.
			However, it will not accept a geometry or box2d text representation, since those do not auto-cast.</para>
		</note>

		<para>&Z_support;</para>
		<para>&curve_support;</para>
	  </refsection>


	  <refsection>
		<title>Examples</title>

		<programlisting>SELECT ST_XMax('BOX3D(1 2 3, 4 5 6)');
st_xmax
-------
4

SELECT ST_XMax(ST_GeomFromText('LINESTRING(1 3 4, 5 6 7)'));
st_xmax
-------
5

SELECT ST_XMax(CAST('BOX(-3 2, 3 4)' As box2d));
st_xmax
-------
3
--Observe THIS DOES NOT WORK because it will try to auto-cast the string representation to a BOX3D
SELECT ST_XMax('LINESTRING(1 3, 5 6)');

--ERROR:  BOX3D parser - doesn't start with BOX3D(

SELECT ST_XMax(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)'));
st_xmax
--------
220288.248780547
		</programlisting>
	  </refsection>

	  <!-- Optionally add a "See Also" section -->
	  <refsection>
		<title>See Also</title>

		<para><xref linkend="ST_XMin" />, <xref linkend="ST_YMax" />, <xref linkend="ST_YMin" />, <xref linkend="ST_ZMax" />, <xref linkend="ST_ZMin" /></para>
	  </refsection>
	</refentry>

	<refentry id="ST_XMin">
	  <refnamediv>
		<refname>ST_XMin</refname>

		<refpurpose>Returns the X minima of a 2D or 3D bounding box or a geometry.</refpurpose>
	  </refnamediv>

	  <refsynopsisdiv>
		<funcsynopsis>
		  <funcprototype>
			<funcdef>float <function>ST_XMin</function></funcdef>
			<paramdef><type>box3d </type> <parameter>aGeomorBox2DorBox3D</parameter></paramdef>
		  </funcprototype>
		</funcsynopsis>
	  </refsynopsisdiv>

	  <refsection>
		<title>Description</title>

		<para>Returns the X minima of a 2D or 3D bounding box or a geometry.</para>

		<note>
		  <para>Although this function is only defined for box3d, it also works for box2d and geometry values due to automatic casting.
			However it will not accept a geometry or box2d text representation, since those do not auto-cast.</para>
		</note>

		<para>&Z_support;</para>
		<para>&curve_support;</para>
	  </refsection>


	  <refsection>
		<title>Examples</title>

		<programlisting>SELECT ST_XMin('BOX3D(1 2 3, 4 5 6)');
st_xmin
-------
1

SELECT ST_XMin(ST_GeomFromText('LINESTRING(1 3 4, 5 6 7)'));
st_xmin
-------
1

SELECT ST_XMin(CAST('BOX(-3 2, 3 4)' As box2d));
st_xmin
-------
-3
--Observe THIS DOES NOT WORK because it will try to auto-cast the string representation to a BOX3D
SELECT ST_XMin('LINESTRING(1 3, 5 6)');

--ERROR:  BOX3D parser - doesn't start with BOX3D(

SELECT ST_XMin(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)'));
st_xmin
--------
220186.995121892
		</programlisting>
	  </refsection>

	  <!-- Optionally add a "See Also" section -->
	  <refsection>
		<title>See Also</title>

		<para><xref linkend="ST_XMax" />, <xref linkend="ST_YMax" />, <xref linkend="ST_YMin" />, <xref linkend="ST_ZMax" />, <xref linkend="ST_ZMin" /></para>
	  </refsection>
	</refentry>

	<refentry id="ST_YMax">
	  <refnamediv>
		<refname>ST_YMax</refname>

		<refpurpose>Returns the Y maxima of a 2D or 3D bounding box or a geometry.</refpurpose>
	  </refnamediv>

	  <refsynopsisdiv>
		<funcsynopsis>
		  <funcprototype>
			<funcdef>float <function>ST_YMax</function></funcdef>
			<paramdef><type>box3d </type> <parameter>aGeomorBox2DorBox3D</parameter></paramdef>
		  </funcprototype>
		</funcsynopsis>
	  </refsynopsisdiv>

	  <refsection>
		<title>Description</title>

		<para>Returns the Y maxima of a 2D or 3D bounding box or a geometry.</para>

		<note>
		  <para>Although this function is only defined for box3d, it also works for box2d and geometry values due to automatic casting.
			However it will not accept a geometry or box2d text representation, since those do not auto-cast.</para>
		</note>

		<para>&Z_support;</para>
		<para>&curve_support;</para>
	  </refsection>


	  <refsection>
		<title>Examples</title>

		<programlisting>SELECT ST_YMax('BOX3D(1 2 3, 4 5 6)');
st_ymax
-------
5

SELECT ST_YMax(ST_GeomFromText('LINESTRING(1 3 4, 5 6 7)'));
st_ymax
-------
6

SELECT ST_YMax(CAST('BOX(-3 2, 3 4)' As box2d));
st_ymax
-------
4
--Observe THIS DOES NOT WORK because it will try to auto-cast the string representation to a BOX3D
SELECT ST_YMax('LINESTRING(1 3, 5 6)');

--ERROR:  BOX3D parser - doesn't start with BOX3D(

SELECT ST_YMax(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)'));
st_ymax
--------
150506.126829327
		</programlisting>
	  </refsection>

	  <!-- Optionally add a "See Also" section -->
	  <refsection>
		<title>See Also</title>

		<para><xref linkend="ST_XMin" />, <xref linkend="ST_XMax" />, <xref linkend="ST_YMin" />, <xref linkend="ST_ZMax" />, <xref linkend="ST_ZMin" /></para>
	  </refsection>
	</refentry>

	<refentry id="ST_YMin">
	  <refnamediv>
		<refname>ST_YMin</refname>

		<refpurpose>Returns the Y minima of a 2D or 3D bounding box or a geometry.</refpurpose>
	  </refnamediv>

	  <refsynopsisdiv>
		<funcsynopsis>
		  <funcprototype>
			<funcdef>float <function>ST_YMin</function></funcdef>
			<paramdef><type>box3d </type> <parameter>aGeomorBox2DorBox3D</parameter></paramdef>
		  </funcprototype>
		</funcsynopsis>
	  </refsynopsisdiv>

	  <refsection>
		<title>Description</title>

		<para>Returns the Y minima of a 2D or 3D bounding box or a geometry.</para>

		<note>
		  <para>Although this function is only defined for box3d, it also works for box2d and geometry values due to automatic casting.
			However it will not accept a geometry or box2d text representation, since those do not auto-cast.</para>
		</note>

		<para>&Z_support;</para>
		<para>&curve_support;</para>
	  </refsection>


	  <refsection>
		<title>Examples</title>

		<programlisting>SELECT ST_YMin('BOX3D(1 2 3, 4 5 6)');
st_ymin
-------
2

SELECT ST_YMin(ST_GeomFromText('LINESTRING(1 3 4, 5 6 7)'));
st_ymin
-------
3

SELECT ST_YMin(CAST('BOX(-3 2, 3 4)' As box2d));
st_ymin
-------
2
--Observe THIS DOES NOT WORK because it will try to auto-cast the string representation to a BOX3D
SELECT ST_YMin('LINESTRING(1 3, 5 6)');

--ERROR:  BOX3D parser - doesn't start with BOX3D(

SELECT ST_YMin(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)'));
st_ymin
--------
150406
		</programlisting>
	  </refsection>

	  <!-- Optionally add a "See Also" section -->
	  <refsection>
		<title>See Also</title>

		<para><xref linkend="ST_GeomFromEWKT" />, <xref linkend="ST_XMin" />, <xref linkend="ST_XMax" />, <xref linkend="ST_YMax" />, <xref linkend="ST_ZMax" />, <xref linkend="ST_ZMin" /></para>
	  </refsection>
	</refentry>

	<refentry id="ST_ZMax">
	  <refnamediv>
		<refname>ST_ZMax</refname>

		<refpurpose>Returns the Z maxima of a 2D or 3D bounding box or a geometry.</refpurpose>
	  </refnamediv>

	  <refsynopsisdiv>
		<funcsynopsis>
		  <funcprototype>
			<funcdef>float <function>ST_ZMax</function></funcdef>
			<paramdef><type>box3d </type> <parameter>aGeomorBox2DorBox3D</parameter></paramdef>
		  </funcprototype>
		</funcsynopsis>
	  </refsynopsisdiv>

	  <refsection>
		<title>Description</title>

		<para>Returns the Z maxima of a 2D or 3D bounding box or a geometry.</para>

		<note>
		  <para>Although this function is only defined for box3d, it also works for box2d and geometry values due to automatic casting.
			However it will not accept a geometry or box2d text representation, since those do not auto-cast.</para>
		</note>

		<para>&Z_support;</para>
		<para>&curve_support;</para>
	  </refsection>


	  <refsection>
		<title>Examples</title>

		<programlisting>SELECT ST_ZMax('BOX3D(1 2 3, 4 5 6)');
st_zmax
-------
6

SELECT ST_ZMax(ST_GeomFromEWKT('LINESTRING(1 3 4, 5 6 7)'));
st_zmax
-------
7

SELECT ST_ZMax('BOX3D(-3 2 1, 3 4 1)' );
st_zmax
-------
1
--Observe THIS DOES NOT WORK because it will try to auto-cast the string representation to a BOX3D
SELECT ST_ZMax('LINESTRING(1 3 4, 5 6 7)');

--ERROR:  BOX3D parser - doesn't start with BOX3D(

SELECT ST_ZMax(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)'));
st_zmax
--------
3
		</programlisting>
	  </refsection>

	  <!-- Optionally add a "See Also" section -->
	  <refsection>
		<title>See Also</title>

		<para><xref linkend="ST_GeomFromEWKT" />, <xref linkend="ST_XMin" />, <xref linkend="ST_XMax" />, <xref linkend="ST_YMax" />, <xref linkend="ST_YMin" />, <xref linkend="ST_ZMax" /></para>
	  </refsection>
	</refentry>

	<refentry id="ST_ZMin">
	  <refnamediv>
		<refname>ST_ZMin</refname>

		<refpurpose>Returns the Z minima of a 2D or 3D bounding box or a geometry.</refpurpose>
	  </refnamediv>

	  <refsynopsisdiv>
		<funcsynopsis>
		  <funcprototype>
			<funcdef>float <function>ST_ZMin</function></funcdef>
			<paramdef><type>box3d </type> <parameter>aGeomorBox2DorBox3D</parameter></paramdef>
		  </funcprototype>
		</funcsynopsis>
	  </refsynopsisdiv>

	  <refsection>
		<title>Description</title>

		<para>Returns the Z minima of a 2D or 3D bounding box or a geometry.</para>

		<note>
		  <para>Although this function is only defined for box3d, it also works for box2d and geometry values due to automatic casting.
			However it will not accept a geometry or box2d text representation, since those do not auto-cast.</para>
		</note>

		<para>&Z_support;</para>
		<para>&curve_support;</para>
	  </refsection>


	  <refsection>
		<title>Examples</title>

		<programlisting>SELECT ST_ZMin('BOX3D(1 2 3, 4 5 6)');
st_zmin
-------
3

SELECT ST_ZMin(ST_GeomFromEWKT('LINESTRING(1 3 4, 5 6 7)'));
st_zmin
-------
4

SELECT ST_ZMin('BOX3D(-3 2 1, 3 4 1)' );
st_zmin
-------
1
--Observe THIS DOES NOT WORK because it will try to auto-cast the string representation to a BOX3D
SELECT ST_ZMin('LINESTRING(1 3 4, 5 6 7)');

--ERROR:  BOX3D parser - doesn't start with BOX3D(

SELECT ST_ZMin(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)'));
st_zmin
--------
1
		</programlisting>
	  </refsection>

	  <!-- Optionally add a "See Also" section -->
	  <refsection>
		<title>See Also</title>

		<para><xref linkend="ST_GeomFromEWKT" />, <xref linkend="ST_GeomFromText" />, <xref linkend="ST_XMin" />, <xref linkend="ST_XMax" />, <xref linkend="ST_YMax" />, <xref linkend="ST_YMin" />, <xref linkend="ST_ZMax" /></para>
	  </refsection>
	</refentry>

 </sect1>
