<?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 the geometry.</refpurpose>
	  </refnamediv>

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

	  <refsection>
		<title>Description</title>

		<para>Returns a BOX2D 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)

	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 the geometry.</refpurpose>
	  </refnamediv>

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

	  <refsection>
		<title>Description</title>

		<para>Returns a BOX3D 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)

	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>Return 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>Return the 'estimated' extent of the given spatial table.
			The estimated is taken from the geometry column's statistics. The
			current schema will be used if not specified. The default behavior
			is to also use statistics collected from child tables (tables
			with INHERITS) if available. If 'parent_only' 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 resulting extent will be about 95% of the real
		one.</para>

                <note>
                <para>
In 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>For PostgreSQL&lt;8.0.0 statistics are gathered by
		update_geometry_stats() and resulting extent will be exact.</para>

    <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', 'the_geom');
--result--
BOX(-8877653 4912316,-8010225.5 5589284)

SELECT ST_EstimatedExtent('feature_poly', 'the_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" /></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>This function 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 in all
			directions, or by specifying an expansion distance for each direction.

			Uses double-precision. Can be very useful 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 geometry version of ST_Expand, which is the most commonly used, variants
			are provided that accept and produce internal BOX2D and BOX3D data types.
		</para>
		<para>ST_Expand is similar in concept to <xref linkend="ST_Buffer" />,
			except while buffer expands the geometry in all directions,
			ST_Expand expands the bounding box along each axis.</para>
		<para>Units are in the units of the spatial reference system in use denoted by the SRID.</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>the_geom &amp;&amp; ST_Expand('POINT(10 20)', 10) AND ST_Distance(the_geom, 'POINT(10 20)') &lt; 10</code>.
			This has been replaced by the easier <xref linkend="ST_DWithin" /> construct.</para>
		</note>

		<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>
		</note>

		<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_AsEWKT" />, <xref linkend="ST_Buffer" />, <xref linkend="ST_DWithin" />, <xref linkend="ST_GeomFromEWKT" />, <xref linkend="ST_GeomFromText" />, <xref linkend="ST_SRID" /></para>
	  </refsection>
	</refentry>

	<refentry id="ST_Extent">
	  <refnamediv>
		<refname>ST_Extent</refname>
		<refpurpose>an aggregate function that returns the bounding box that bounds rows 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>ST_Extent returns a bounding box that encloses a set of geometries. The ST_Extent function is an "aggregate" function in the
			terminology of SQL. That means that it operates on lists
			of data, in the same way the SUM() and AVG() functions do.</para>
		<para>Since it returns a bounding box, the spatial Units are in the units of the spatial reference system in use denoted by the SRID</para>
		<para>ST_Extent is similar in concept to Oracle Spatial/Locator's SDO_AGGR_MBR</para>
		<note>
		  <para>Since ST_Extent returns a bounding box, the SRID meta-data is lost.  Use ST_SetSRID to force it back into
			a geometry with SRID meta data.  The coordinates are in the units of the spatial ref of the orginal geometries.</para>
		</note>

		<note>
		  <para>ST_Extent will return boxes with only an x and y component even with (x,y,z) coordinate geometries.  To maintain x,y,z use ST_3DExtent instead.</para>
		</note>

		<note>
		  <para>Availability: 1.4.0</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(the_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(the_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(the_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="geometry_overlaps" />, <xref linkend="ST_AsEWKT" />, <xref linkend="ST_3DExtent" />, <xref linkend="ST_SetSRID" />, <xref linkend="ST_SRID" /></para>
	  </refsection>
	</refentry>

	<refentry id="ST_3DExtent">
	  <refnamediv>
		<refname>ST_3DExtent</refname>
		<refpurpose>an aggregate function that returns the 3D bounding box that bounds rows 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>ST_3DExtent returns a box3d (includes Z coordinate) bounding box that encloses a set of geometries. The ST_3DExtent function is an "aggregate" function in the
			terminology of SQL. That means that it operates on lists
			of data, in the same way the SUM() and AVG() functions do.</para>
		<para>Since it returns a bounding box, the spatial Units are in the units of the spatial reference system in use denoted by the SRID</para>

		<note>
		  <para>Since ST_3DExtent returns a bounding box, the SRID meta-data is lost.  Use ST_SetSRID to force it back into
			a geometry with SRID meta data.  The coordinates are in the units of the spatial ref of the orginal 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.the_geom) As b3extent
FROM (SELECT ST_MakePoint(x,y,z) As the_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.the_geom) As b3extent
FROM (SELECT ST_Translate(ST_Force_3DZ(ST_LineToCurve(ST_Buffer(ST_MakePoint(x,y),1))),0,0,z) As the_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" /></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 BOX2D defined by the given 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, the_geom
FROM features
WHERE the_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_MakePoint" />, <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 BOX3D defined by the given 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 autocast 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 autocast 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 autocast 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 autocast 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 autocast 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 autocast 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>
