<!-- Converted by db4-upgrade version 1.1 -->
<section xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="BBox_Functions">
      <title>Bounding Box Functions</title><info>
        <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>
    </info>



    <refentry xml: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 role="enhanced" conformance="2.0.0">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 language="sql">SELECT Box2D('LINESTRING(1 2,3 4,5 6)'::geometry);</programlisting>
<screen role="text-primary">BOX(1 2,5 6)</screen>
<programlisting language="sql">SELECT Box2D('CIRCULARSTRING(220268 150415,220227 150505,220227 150406)'::geometry);</programlisting>
<screen role="text-primary">BOX(220186.99512189245 150406,220288.24878054656 150506.12682932706)</screen>
      </refsection>

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

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

    <refentry xml: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 role="enhanced" conformance="2.0.0">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 language="sql">SELECT Box3D('LINESTRING(1 2 3,3 4 5,5 6 5)'::geometry);</programlisting>
<screen role="text-primary">BOX3D(1 2 3,5 6 5)</screen>
<programlisting language="sql">SELECT Box3D('CIRCULARSTRING(220268 150415 1,220227 150505 1,220227 150406 1)'::geometry);</programlisting>
<screen role="text-primary">BOX3D(220186.99512189245 150406 1,220288.24878054656 150506.12682932706 1)</screen>
      </refsection>

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

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

    <refentry xml: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>

        <note>
            <para>
            Escaping names for tables and/or namespaces that include special characters and quotes may require special handling. A user notes: "For schemas and tables, use identifier escaping rules to produce a double-quoted string, and afterwards remove the first and last double-quote character. For geometry column pass as is."
            </para>
        </note>

    <para role="availability" conformance="1.0.0">Availability: 1.0.0</para>
    <para role="changed" conformance="2.1.0.">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 language="sql" role="requires-external-state">SELECT ST_EstimatedExtent('ny', 'edges', 'geom');</programlisting>
<screen role="text-primary">                st_estimatedextent
--------------------------------------------------
 BOX(-8877653 4912316,-8010225.5 5589284)
(1 row)</screen>

<programlisting language="sql" role="requires-external-state">SELECT ST_EstimatedExtent('feature_poly', 'geom');</programlisting>
<screen role="text-primary">                         st_estimatedextent
---------------------------------------------------------------------
 BOX(-124.659652709961 24.6830825805664,-67.7798080444336 49.0012092590332)
(1 row)</screen>
      </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 xml: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 role="availability" conformance="1.5.0">Availability: 1.5.0 behavior changed to output double precision instead of float4 coordinates.</para>
        <para role="enhanced" conformance="2.0.0">Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.</para>
        <para role="enhanced" conformance="2.3.0">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>
        <para>10-meter expanded box around bbox of a linestring.</para>
        <!-- TODO: fix results of documentation to reflect new behavior -->
        <programlisting language="sql">SELECT CAST(ST_Expand(ST_GeomFromText('LINESTRING(2312980 110676,2312923 110701,2312892 110714)', 2163), 10) As box2d);</programlisting>
<screen role="text-primary">BOX(2312882 110666,2312990 110724)</screen>
<para>This example expands a 3D box by 10 meters.</para>
<programlisting language="sql">SELECT ST_Expand(CAST('BOX3D(778783 2951741 1,794875 2970042.61545891 10)' AS box3d), 10)</programlisting>
<screen role="text-primary">BOX3D(778773 2951731 -9,794885 2970052.61545891 20)</screen>
<para>This example renders the text representation of a 10-meter expanded box around a point geometry.</para>
<programlisting language="sql">SELECT ST_Expand('SRID=2163;POINT(2312980 110676)'::geometry, 10);</programlisting>
<screen role="visual-primary text-primary">SRID=2163;POLYGON((2312970 110666,2312970 110686,2312990 110686,2312990 110666,2312970 110666))</screen>
      </refsection>

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

    <refentry xml: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 role="enhanced" conformance="2.0.0">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 language="sql">SELECT ST_Extent(geom) AS bextent FROM sometable;</programlisting>
<screen role="text-primary">BOX(739651.875 2908247.25,794875.8125 2970042.75)</screen>
        <para>Return extent of each geometry category.</para>
<programlisting language="sql">SELECT ST_Extent(geom) as bextent
FROM sometable
GROUP BY category ORDER BY category;</programlisting>
<screen role="text-primary">                      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</screen>
<para>This example converts the extent back into a geometry and renders its extended text representation.</para>
<programlisting language="sql">SELECT ST_SetSRID(ST_Extent(geom), 2249) AS bextent FROM sometable;</programlisting>
<screen role="text-primary"> SRID=2249;POLYGON((739651.875 2908247.25,739651.875 2970042.75,794875.8125 2970042.75,
794875.8125 2908247.25,739651.875 2908247.25))
        </screen>
      </refsection>

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

    <refentry xml: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 role="enhanced" conformance="2.0.0">Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.</para>
        <para role="changed" conformance="2.0.0">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 language="sql">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;</programlisting>
<screen role="text-primary">BOX3D(1 1 0,3 2 2)</screen>
<para>This example returns the extent of several elevated CircularStrings.</para>
<programlisting language="sql">
SELECT ST_3DExtent(foo.geom) As b3extent
FROM (SELECT ST_Translate(ST_Force3DZ(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;</programlisting>
<screen role="text-primary">BOX3D(0 0 0,4 3 2)</screen>
      </refsection>

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

    <refentry xml: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>

        <para>Return all features that fall within 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).</para>
        <programlisting language="sql"><![CDATA[
SELECT feature_id, feature_name, geom
FROM features
WHERE geom && 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 xml: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 role="changed" conformance="2.0.0">Changed: 2.0.0 In prior versions this used to be called ST_MakeBox3D</para>
      </refsection>


      <refsection>
        <title>Examples</title>

        <programlisting language="sql">
SELECT ST_3DMakeBox(ST_MakePoint(-989502.1875, 528439.5625, 10),
    ST_MakePoint(-987121.375 , 529933.1875, 10))</programlisting>
<screen role="text-primary">BOX3D(-989502.1875 528439.5625 10,-987121.375 529933.1875 10)</screen>
      </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 xml: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 language="sql">SELECT ST_XMax('BOX3D(1 2 3,4 5 6)');</programlisting>
<screen role="text-primary">4</screen>
<programlisting language="sql">SELECT ST_XMax('LINESTRING(1 3 4,5 6 7)'::geometry);</programlisting>
<screen role="text-primary">5</screen>
<programlisting language="sql">SELECT ST_XMax(CAST('BOX(-3 2,3 4)' AS box2d));</programlisting>
<screen role="text-primary">3</screen>
<para>Observe THIS DOES NOT WORK because it will try to auto-cast the string representation to a BOX3D.</para>
<programlisting language="sql">SELECT ST_XMax('LINESTRING(1 3,5 6)');</programlisting>
<screen role="text-primary">ERROR: BOX3D parser - doesn't start with BOX3D(</screen>
<programlisting language="sql">SELECT ST_XMax('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)'::geometry);</programlisting>
<screen role="text-primary">220288.248780547</screen>
      </refsection>

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

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

    <refentry xml: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 language="sql">SELECT ST_XMin('BOX3D(1 2 3,4 5 6)');</programlisting>
<screen role="text-primary">1</screen>
<programlisting language="sql">SELECT ST_XMin('LINESTRING(1 3 4,5 6 7)'::geometry);</programlisting>
<screen role="text-primary">1</screen>
<programlisting language="sql">SELECT ST_XMin(CAST('BOX(-3 2,3 4)' AS box2d));</programlisting>
<screen role="text-primary">-3</screen>
<para>Observe THIS DOES NOT WORK because it will try to auto-cast the string representation to a BOX3D.</para>
<programlisting language="sql">SELECT ST_XMin('LINESTRING(1 3,5 6)');</programlisting>
<screen role="text-primary">ERROR: BOX3D parser - doesn't start with BOX3D(</screen>
<programlisting language="sql">SELECT ST_XMin('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)'::geometry);</programlisting>
<screen role="text-primary">220186.995121892</screen>
      </refsection>

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

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

    <refentry xml: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 language="sql">SELECT ST_YMax('BOX3D(1 2 3,4 5 6)');</programlisting>
<screen role="text-primary">5</screen>
<programlisting language="sql">SELECT ST_YMax('LINESTRING(1 3 4,5 6 7)'::geometry);</programlisting>
<screen role="text-primary">6</screen>
<programlisting language="sql">SELECT ST_YMax(CAST('BOX(-3 2,3 4)' AS box2d));</programlisting>
<screen role="text-primary">4</screen>
<para>Observe THIS DOES NOT WORK because it will try to auto-cast the string representation to a BOX3D.</para>
<programlisting language="sql">SELECT ST_YMax('LINESTRING(1 3,5 6)');</programlisting>
<screen role="text-primary">ERROR: BOX3D parser - doesn't start with BOX3D(</screen>
<programlisting language="sql">SELECT ST_YMax('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)'::geometry);</programlisting>
<screen role="text-primary">150506.126829327</screen>
      </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_ZMin"/>, <xref linkend="ST_ZMax"/>, <xref linkend="ST_MMin"/>, <xref linkend="ST_MMax"/></para>
      </refsection>
    </refentry>

    <refentry xml: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 language="sql">SELECT ST_YMin('BOX3D(1 2 3,4 5 6)');</programlisting>
<screen role="text-primary">2</screen>
<programlisting language="sql">SELECT ST_YMin('LINESTRING(1 3 4,5 6 7)'::geometry);</programlisting>
<screen role="text-primary">3</screen>
<programlisting language="sql">SELECT ST_YMin(CAST('BOX(-3 2,3 4)' AS box2d));</programlisting>
<screen role="text-primary">2</screen>
<para>Observe THIS DOES NOT WORK because it will try to auto-cast the string representation to a BOX3D.</para>
<programlisting language="sql">SELECT ST_YMin('LINESTRING(1 3,5 6)');</programlisting>
<screen role="text-primary">ERROR: BOX3D parser - doesn't start with BOX3D(</screen>
<programlisting language="sql">SELECT ST_YMin('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)'::geometry);</programlisting>
<screen role="text-primary">150406</screen>
      </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_ZMin"/>, <xref linkend="ST_ZMax"/>, <xref linkend="ST_MMin"/>, <xref linkend="ST_MMax"/></para>
      </refsection>
    </refentry>

    <refentry xml: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 language="sql">SELECT ST_ZMax('BOX3D(1 2 3,4 5 6)');</programlisting>
<screen role="text-primary">6</screen>
<programlisting language="sql">SELECT ST_ZMax('LINESTRING(1 3 4,5 6 7)'::geometry);</programlisting>
<screen role="text-primary">7</screen>
<programlisting language="sql">SELECT ST_ZMax('BOX3D(-3 2 1,3 4 1)');</programlisting>
<screen role="text-primary">1</screen>
<para>Observe THIS DOES NOT WORK because it will try to auto-cast the string representation to a BOX3D.</para>
<programlisting language="sql">SELECT ST_ZMax('LINESTRING(1 3 4,5 6 7)');</programlisting>
<screen role="text-primary">ERROR: BOX3D parser - doesn't start with BOX3D(</screen>
<programlisting language="sql">SELECT ST_ZMax('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)'::geometry);</programlisting>
<screen role="text-primary">3</screen>
      </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_YMin"/>, <xref linkend="ST_YMax"/>, <xref linkend="ST_ZMin"/>, <xref linkend="ST_MMin"/>, <xref linkend="ST_MMax"/></para>
      </refsection>
    </refentry>

    <refentry xml: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 language="sql">SELECT ST_ZMin('BOX3D(1 2 3,4 5 6)');</programlisting>
<screen role="text-primary">3</screen>
<programlisting language="sql">SELECT ST_ZMin('LINESTRING(1 3 4,5 6 7)'::geometry);</programlisting>
<screen role="text-primary">4</screen>
<programlisting language="sql">SELECT ST_ZMin('BOX3D(-3 2 1,3 4 1)');</programlisting>
<screen role="text-primary">1</screen>
<para>Observe THIS DOES NOT WORK because it will try to auto-cast the string representation to a BOX3D.</para>
<programlisting language="sql">SELECT ST_ZMin('LINESTRING(1 3 4,5 6 7)');</programlisting>
<screen role="text-primary">ERROR: BOX3D parser - doesn't start with BOX3D(</screen>
<programlisting language="sql">SELECT ST_ZMin('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)'::geometry);</programlisting>
<screen role="text-primary">1</screen>
      </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_YMin"/>, <xref linkend="ST_YMax"/>, <xref linkend="ST_ZMax"/>, <xref linkend="ST_MMin"/>, <xref linkend="ST_MMax"/></para>
      </refsection>
    </refentry>

    <refentry xml:id="ST_XSize">
      <refnamediv>
        <refname>ST_XSize</refname>

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

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

      <refsection>
        <title>Description</title>

        <para>Returns the X size of a 2D or 3D bounding box or a geometry, computed as <code>ST_XMax(aGeomorBox2DorBox3D) - ST_XMin(aGeomorBox2DorBox3D)</code>.</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>
        <para role="availability" conformance="3.7.0">Availability: 3.7.0</para>
      </refsection>

      <refsection>
        <title>Examples</title>

        <programlisting language="sql">SELECT ST_XSize('BOX3D(1 2 3,4 5 6)');</programlisting>
<screen role="text-primary">3</screen>
<programlisting language="sql">SELECT ST_XSize('LINESTRING(1 3,5 6)'::geometry);</programlisting>
<screen role="text-primary">4</screen>
      </refsection>

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

        <para><xref linkend="ST_XMin"/>, <xref linkend="ST_XMax"/>, <xref linkend="ST_YSize"/>, <xref linkend="ST_ZSize"/>, <xref linkend="ST_MSize"/></para>
      </refsection>
    </refentry>

    <refentry xml:id="ST_YSize">
      <refnamediv>
        <refname>ST_YSize</refname>

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

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

      <refsection>
        <title>Description</title>

        <para>Returns the Y size of a 2D or 3D bounding box or a geometry, computed as <code>ST_YMax(aGeomorBox2DorBox3D) - ST_YMin(aGeomorBox2DorBox3D)</code>.</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>
        <para role="availability" conformance="3.7.0">Availability: 3.7.0</para>
      </refsection>

      <refsection>
        <title>Examples</title>

        <programlisting language="sql">SELECT ST_YSize('BOX3D(1 2 3,4 5 6)');</programlisting>
<screen role="text-primary">3</screen>
<programlisting language="sql">SELECT ST_YSize('LINESTRING(1 3,5 6)'::geometry);</programlisting>
<screen role="text-primary">3</screen>
      </refsection>

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

        <para><xref linkend="ST_YMin"/>, <xref linkend="ST_YMax"/>, <xref linkend="ST_XSize"/>, <xref linkend="ST_ZSize"/>, <xref linkend="ST_MSize"/></para>
      </refsection>
    </refentry>

    <refentry xml:id="ST_ZSize">
      <refnamediv>
        <refname>ST_ZSize</refname>

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

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

      <refsection>
        <title>Description</title>

        <para>Returns the Z size of a 2D or 3D bounding box or a geometry, computed as <code>ST_ZMax(aGeomorBox2DorBox3D) - ST_ZMin(aGeomorBox2DorBox3D)</code>.</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>
        <para role="availability" conformance="3.7.0">Availability: 3.7.0</para>
      </refsection>

      <refsection>
        <title>Examples</title>

        <programlisting language="sql">SELECT ST_ZSize('BOX3D(1 2 3,4 5 6)');</programlisting>
<screen role="text-primary">3</screen>
<programlisting language="sql">SELECT ST_ZSize('LINESTRING(1 3 4,5 6 7)'::geometry);</programlisting>
<screen role="text-primary">3</screen>
      </refsection>

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

        <para><xref linkend="ST_ZMin"/>, <xref linkend="ST_ZMax"/>, <xref linkend="ST_XSize"/>, <xref linkend="ST_YSize"/>, <xref linkend="ST_MSize"/></para>
      </refsection>
    </refentry>

    <refentry xml:id="ST_MMin">
      <refnamediv>
        <refname>ST_MMin</refname>

        <refpurpose>Returns the M minima of a geometry.</refpurpose>
      </refnamediv>

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

      <refsection>
        <title>Description</title>

        <para>Returns the M minima of a geometry, or null if the geometry lacks M values.</para>

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

      <refsection>
        <title>Examples</title>

        <programlisting language="sql">SELECT ST_MMin('POINT M (1 2 3)');</programlisting>
<screen role="text-primary">3</screen>
      </refsection>

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

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


    <refentry xml:id="ST_MMax">
      <refnamediv>
        <refname>ST_MMax</refname>

        <refpurpose>Returns the M maxima of a geometry.</refpurpose>
      </refnamediv>

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

      <refsection>
        <title>Description</title>
        <para>Returns the M maxima of a geometry, or null if the geometry lacks M values.</para>

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

      <refsection>
        <title>Examples</title>
        <programlisting language="sql">SELECT ST_MMax('POINT M (1 2 3)');</programlisting>
<screen role="text-primary">3</screen>
      </refsection>

      <refsection>
        <title>See Also</title>
        <para><xref linkend="ST_XMin"/>, <xref linkend="ST_XMax"/>, <xref linkend="ST_YMin"/>, <xref linkend="ST_YMax"/>, <xref linkend="ST_ZMin"/>, <xref linkend="ST_ZMax"/>, <xref linkend="ST_MMin"/>, <xref linkend="ST_MSize"/></para>
      </refsection>
    </refentry>

    <refentry xml:id="ST_MSize">
      <refnamediv>
        <refname>ST_MSize</refname>

        <refpurpose>Returns the M size of a geometry.</refpurpose>
      </refnamediv>

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

      <refsection>
        <title>Description</title>
        <para>Returns the M size of a geometry, computed as <code>ST_MMax(geom) - ST_MMin(geom)</code>, or null if the geometry lacks M values.</para>

        <para>&Z_support;</para>
        <para>&curve_support;</para>
        <para role="availability" conformance="3.7.0">Availability: 3.7.0</para>
      </refsection>

      <refsection>
        <title>Examples</title>
        <programlisting language="sql">SELECT ST_MSize('LINESTRING M (1 2 3,4 6 8)');</programlisting>
<screen role="text-primary">5</screen>
      </refsection>

      <refsection>
        <title>See Also</title>
        <para><xref linkend="ST_MMin"/>, <xref linkend="ST_MMax"/>, <xref linkend="ST_XSize"/>, <xref linkend="ST_YSize"/>, <xref linkend="ST_ZSize"/></para>
      </refsection>
    </refentry>

 </section>
