</listitem>
</varlistentry>
- <varlistentry id="IsClosed">
- <term>ST_IsClosed(geometry)</term>
-
- <listitem>
- <para>Returns true of the geometry start and end points are
- coincident.</para>
- </listitem>
- </varlistentry>
-
<varlistentry>
<term>ST_IsRing(geometry)</term>
</listitem>
</varlistentry>
- <varlistentry id="ST_IsClosed">
- <term>ST_IsClosed</term>
-
- <listitem>
- <para>Test if an ST_Curve or ST_MultiCurve value is closed.</para>
-
- <note>
- <para>SQL-MM defines the result of ST_IsClosed(NULL) to be 0,
- while PostGIS returns NULL.</para>
- </note>
-
- <para>SQL-MM 3: 7.1.5, 9.3.3</para>
- </listitem>
- </varlistentry>
-
<varlistentry>
<term>ST_IsEmpty</term>
</listitem>
</varlistentry>
- <varlistentry>
+ <varlistentry id="ST_IsRing">
<term>ST_IsRing</term>
<listitem>
</listitem>
</varlistentry>
- <varlistentry>
+ <varlistentry >
<term>ST_IsSimple</term>
<listitem>
<para><xref linkend="GeometryType" /></para>
</refsection>
</refentry>
+
+ <refentry id="ST_IsClosed">
+ <refnamediv>
+ <refname>ST_IsClosed</refname>
+
+ <refpurpose>Returns <varname>TRUE</varname> if the
+ <varname>LINESTRING</varname>'s start and end points are coincident.
+ </refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <funcsynopsis>
+ <funcprototype>
+ <funcdef>boolean <function>ST_IsClosed</function></funcdef>
+
+ <paramdef><type>geometry </type> <parameter>g</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
+
+ <refsection>
+ <title>Description</title>
+
+ <para>Returns <varname>TRUE</varname> if the <varname>LINESTRING</varname>'s
+ start and end points are coincident.</para>
+
+ <para><inlinemediaobject>
+ <imageobject>
+ <imagedata fileref="images/check.png" />
+ </imageobject>
+ </inlinemediaobject> This method implements the <ulink
+ url="http://www.opengeospatial.org/standards/sfs">OpenGIS Simple Features
+ Implementation Specification for SQL.</ulink></para>
+
+ <para><inlinemediaobject>
+ <imageobject>
+ <imagedata fileref="images/check.png" />
+ </imageobject>
+ </inlinemediaobject> This method implements the SQL/MM specification:
+ SQL-MM 3: 7.1.5, 9.3.3</para>
+
+ <note>
+ <para>SQL-MM defines the result of
+ <function>ST_IsClosed(<varname>NULL</varname>)</function> to be 0, while
+ PostGIS returns <varname>NULL</varname>.</para>
+ </note>
+ </refsection>
+
+ <refsection>
+ <title>Examples</title>
+
+ <programlisting>postgis=# SELECT ST_IsClosed('LINESTRING(0 0, 1 1)'::geometry);
+ st_isclosed
+-------------
+ f
+(1 row)
+
+postgis=# SELECT ST_IsClosed('LINESTRING(0 0, 0 1, 1 1, 0 0)'::geometry);
+ st_isclosed
+-------------
+ t
+(1 row)
+
+postgis=# SELECT ST_IsClosed('MULTILINESTRING((0 0, 0 1, 1 1, 0 0),(0 0, 1 1))'::geometry);
+ st_isclosed
+-------------
+ f
+(1 row)
+
+postgis=# SELECT ST_IsClosed('POINT(0 0)'::geometry);
+ st_isclosed
+-------------
+ t
+(1 row)
+
+postgis=# SELECT ST_IsClosed('MULTIPOINT((0 0), (1 1))'::geometry);
+ st_isclosed
+-------------
+ t
+(1 row)</programlisting>
+ </refsection>
+
+ <refsection>
+ <title>See Also</title>
+
+ <para><xref linkend="ST_IsRing" /></para>
+ </refsection>
+ </refentry>
+
<refentry id="ST_NPoints">
<refnamediv>
<refname>ST_NPoints</refname>