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postgis/doc/reference_output.xml
Regina Obe a5395c2354 fill in missing curve support flags for outputs 
git-svn-id: http://svn.osgeo.org/postgis/trunk@4982 b70326c6-7e19-0410-871a-916f4a2858ee
2009-12-03 08:58:12 +00:00

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<?xml version="1.0" encoding="UTF-8"?>
<sect1 id="Geometry_Outputs">
<title>Geometry Outputs</title>
<refentry id="ST_AsBinary">
<refnamediv>
<refname>ST_AsBinary</refname>
<refpurpose>Return the Well-Known Binary (WKB) representation of the geometry/geography without SRID meta data.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
<funcdef>bytea <function>ST_AsBinary</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>bytea <function>ST_AsBinary</function></funcdef>
<paramdef><type>geography </type> <parameter>g1</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>bytea <function>ST_AsBinary</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
<paramdef><type>text </type><parameter>NDR_or_XDR</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsection>
<title>Description</title>
<para>Returns the Well-Known Binary representation of the geometry. There are 2 variants of the function. The first
variant takes no endian encoding paramater and defaults to little endian. The second variant takes a second argument
denoting the encoding - using little-endian ('NDR') or big-endian ('XDR') encoding.</para>
<para>This is useful in binary cursors to pull data out of the
database without converting it to a string representation.</para>
<note>
<para>The WKB spec does not include the SRID. To get the OGC WKB with SRID format use ST_AsEWKB</para>
</note>
<note>
<para>ST_AsBinary is the reverse of <xref linkend="ST_GeomFromWKB" /> for geometry. Use <xref linkend="ST_GeomFromWKB" /> to convert to a postgis geometry from ST_AsBinary representation.</para>
</note>
<para>Availability: 1.5.0 geography support was introduced.</para>
<para>&sfs_compliant; s2.1.1.1</para>
<para>&sqlmm_compliant; SQL-MM 3: 5.1.37</para>
<para>&curve_support;</para>
</refsection>
<refsection>
<title>Examples</title>
<programlisting>SELECT ST_AsBinary(ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326));
st_asbinary
--------------------------------
\001\003\000\000\000\001\000\000\000\005
\000\000\000\000\000\000\000\000\000\000
\000\000\000\000\000\000\000\000\000\000
\000\000\000\000\000\000\000\000\000\000
\000\000\000\360?\000\000\000\000\000\000
\360?\000\000\000\000\000\000\360?\000\000
\000\000\000\000\360?\000\000\000\000\000
\000\000\000\000\000\000\000\000\000\000\000
\000\000\000\000\000\000\000\000
(1 row)</programlisting>
<programlisting>SELECT ST_AsBinary(ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326), 'XDR');
st_asbinary
--------------------------------
\000\000\000\000\003\000\000\000\001\000\000\000\005\000\000\000\000\000
\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000
\000?\360\000\000\000\000\000\000?\360\000\000\000\000\000\000?\360\000\000
\000\000\000\000?\360\000\000\000\000\000\000\000\000\000\000\000\000\000\000
\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000
(1 row)</programlisting>
</refsection>
<!-- Optionally add a "See Also" section -->
<refsection>
<title>See Also</title>
<para><xref linkend="ST_AsEWKB" />, <xref linkend="ST_AsEWKT" />, <xref linkend="ST_AsText" />, <xref linkend="ST_GeomFromEWKB" /></para>
</refsection>
</refentry>
<refentry id="ST_AsEWKB">
<refnamediv>
<refname>ST_AsEWKB</refname>
<refpurpose>Return the Well-Known Binary (WKB) representation of the geometry with SRID meta data.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
<funcdef>bytea <function>ST_AsEWKB</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>bytea <function>ST_AsEWKB</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
<paramdef><type>text </type><parameter>NDR_or_XDR</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsection>
<title>Description</title>
<para>Returns the Well-Known Binary representation of the geometry with SRID metadata. There are 2 variants of the function. The first
variant takes no endian encoding paramater and defaults to little endian. The second variant takes a second argument
denoting the encoding - using little-endian ('NDR') or big-endian ('XDR') encoding.</para>
<para>This is useful in binary cursors to pull data out of the
database without converting it to a string representation.</para>
<note>
<para>The WKB spec does not include the SRID. To get the OGC WKB format use ST_AsBinary</para>
</note>
<note>
<para>ST_AsEWKB is the reverse of ST_GeomFromEWKB. Use ST_GeomFromEWKB to convert to a postgis geometry from ST_AsEWKB representation.</para>
</note>
<para>&Z_support;</para>
<para>&curve_support;</para>
</refsection>
<refsection>
<title>Examples</title>
<programlisting>SELECT ST_AsEWKB(ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326));
st_asewkb
--------------------------------
\001\003\000\000 \346\020\000\000\001\000
\000\000\005\000\000\000\000
\000\000\000\000\000\000\000\000
\000\000\000\000\000\000\000\000\000
\000\000\000\000\000\000\000\000\000\000
\000\000\360?\000\000\000\000\000\000\360?
\000\000\000\000\000\000\360?\000\000\000\000\000
\000\360?\000\000\000\000\000\000\000\000\000\000\000
\000\000\000\000\000\000\000\000\000\000\000\000\000
(1 row)</programlisting>
<programlisting>
SELECT ST_AsEWKB(ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326), 'XDR');
st_asewkb
--------------------------------
\000 \000\000\003\000\000\020\346\000\000\000\001\000\000\000\005\000\000\000\000\
000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000?
\360\000\000\000\000\000\000?\360\000\000\000\000\000\000?\360\000\000\000\000
\000\000?\360\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000
\000\000\000\000\000\000\000\000\000\000\000\000\000
</programlisting>
</refsection>
<!-- Optionally add a "See Also" section -->
<refsection>
<title>See Also</title>
<para><xref linkend="ST_AsBinary" />, <xref linkend="ST_AsEWKT" />, <xref linkend="ST_AsText" />, <xref linkend="ST_GeomFromEWKT" />, <xref linkend="ST_SRID" /></para>
</refsection>
</refentry>
<refentry id="ST_AsEWKT">
<refnamediv>
<refname>ST_AsEWKT</refname>
<refpurpose>Return the Well-Known Text (WKT) representation of the geometry with SRID meta data.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
<funcdef>text <function>ST_AsEWKT</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsection>
<title>Description</title>
<para>Returns the Well-Known Text representation of the geometry prefixed with the SRID.</para>
<note>
<para>The WKT spec does not include the SRID. To get the OGC WKT format use ST_AsText</para>
</note>
<para><inlinegraphic fileref="images/warning.png" />
WKT format does not maintain precision so to prevent floating truncation, use ST_AsBinary or ST_AsEWKB format for transport.
</para>
<note>
<para>ST_AsEWKT is the reverse of <xref linkend="ST_GeomFromEWKT" />. Use <xref linkend="ST_GeomFromEWKT" /> to convert to a postgis geometry from ST_AsEWKT representation.</para>
</note>
<para>&Z_support;</para>
<para>&curve_support;</para>
</refsection>
<refsection>
<title>Examples</title>
<programlisting>SELECT ST_AsEWKT('0103000020E61000000100000005000000000000
000000000000000000000000000000000000000000000000000000
F03F000000000000F03F000000000000F03F000000000000F03
F000000000000000000000000000000000000000000000000'::geometry);
st_asewkt
--------------------------------
SRID=4326;POLYGON((0 0,0 1,1 1,1 0,0 0))
(1 row)
SELECT ST_AsEWKT('0108000080030000000000000060E30A4100000000785C0241000000000000F03F0000000018
E20A4100000000485F024100000000000000400000000018
E20A4100000000305C02410000000000000840')
--st_asewkt---
CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)
</programlisting>
</refsection>
<!-- Optionally add a "See Also" section -->
<refsection>
<title>See Also</title>
<para><xref linkend="ST_AsBinary" /><xref linkend="ST_AsEWKB" /><xref linkend="ST_AsText" />, <xref linkend="ST_GeomFromEWKT" /></para>
</refsection>
</refentry>
<refentry id="ST_AsGeoJSON">
<refnamediv>
<refname>ST_AsGeoJSON</refname>
<refpurpose>Return the geometry as a GeoJSON element.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
<funcdef>text <function>ST_AsGeoJSON</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGeoJSON</function></funcdef>
<paramdef><type>geography </type> <parameter>g1</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGeoJSON</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>max_decimal_digits</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGeoJSON</function></funcdef>
<paramdef><type>geography </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>max_decimal_digits</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGeoJSON</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>max_decimal_digits</parameter></paramdef>
<paramdef><type>integer </type> <parameter>options</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGeoJSON</function></funcdef>
<paramdef><type>geography </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>max_decimal_digits</parameter></paramdef>
<paramdef><type>integer </type> <parameter>options</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGeoJSON</function></funcdef>
<paramdef><type>integer </type> <parameter>version</parameter></paramdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGeoJSON</function></funcdef>
<paramdef><type>integer </type> <parameter>version</parameter></paramdef>
<paramdef><type>geography </type> <parameter>g1</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGeoJSON</function></funcdef>
<paramdef><type>integer </type> <parameter>version</parameter></paramdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>max_decimal_digits</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGeoJSON</function></funcdef>
<paramdef><type>integer </type> <parameter>version</parameter></paramdef>
<paramdef><type>geography </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>max_decimal_digits</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGeoJSON</function></funcdef>
<paramdef><type>integer </type> <parameter>version</parameter></paramdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>max_decimal_digits</parameter></paramdef>
<paramdef><type>integer </type> <parameter>options</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGeoJSON</function></funcdef>
<paramdef><type>integer </type> <parameter>version</parameter></paramdef>
<paramdef><type>geography </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>max_decimal_digits</parameter></paramdef>
<paramdef><type>integer </type> <parameter>options</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsection>
<title>Description</title>
<para>Return the geometry as a Geometry Javascript Object Notation (GeoJSON) element. (Cf <ulink
url="http://geojson.org/geojson-spec.html">GeoJSON
specifications 1.0</ulink>). 2D and 3D Geometries are both
supported. GeoJSON only support SFS 1.1 geometry type (no curve
support for example).</para>
<para>The version parameter, if specified, must be 1.</para>
<para>The third argument may be used to reduce the maximum number
of decimal places used in output (defaults to 15).</para>
<para>The last 'options' argument could be used to add Bbox or Crs
in GeoJSON output:
<itemizedlist>
<listitem>
<para>0: means no option (default value)</para>
</listitem>
<listitem>
<para>1: GeoJSON Bbox</para>
</listitem>
<listitem>
<para>2: GeoJSON Short CRS (e.g EPSG:4326)</para>
</listitem>
<listitem>
<para>4: GeoJSON Long CRS (e.g urn:ogc:def:crs:EPSG:4326)</para>
</listitem>
</itemizedlist>
</para>
<para>Version 1: ST_AsGeoJSON(geom) / precision=15 version=1 options=0</para>
<para>Version 2: ST_AsGeoJSON(geom, precision) / version=1 options=0</para>
<para>Version 3: ST_AsGeoJSON(geom, precision, options) / version=1</para>
<para>Version 4: ST_AsGeoJSON(version, geom) / precision=15 options=0</para>
<para>Version 5: ST_AsGeoJSON(version, geom, precision) /options=0</para>
<para>Version 6: ST_AsGeoJSON(version, geom, precision,options)</para>
<para>Availability: 1.3.4</para>
<para>Availability: 1.5.0 geography support was introduced.</para>
<para>&Z_support;</para>
</refsection>
<refsection>
<title>Examples</title>
<para>GeoJSON format is generally more efficient than other formats for use in ajax mapping.
One popular javascript client that supports this is Open Layers.
Example of its use is <ulink
url="http://openlayers.org/dev/examples/vector-formats.html">OpenLayers GeoJSON Example</ulink>
</para>
<programlisting>SELECT ST_AsGeoJSON(the_geom) from fe_edges limit 1;
st_asgeojson
-----------------------------------------------------------------------------------------------------------
{"type":"MultiLineString","coordinates":[[[-89.734634999999997,31.492072000000000],
[-89.734955999999997,31.492237999999997]]]}
(1 row)
--3d point
SELECT ST_AsGeoJSON('LINESTRING(1 2 3, 4 5 6)');
st_asgeojson
-----------------------------------------------------------------------------------------
{"type":"LineString","coordinates":[[1,2,3],[4,5,6]]}
</programlisting>
</refsection>
</refentry>
<refentry id="ST_AsGML">
<refnamediv>
<refname>ST_AsGML</refname>
<refpurpose>Return the geometry as a GML version 2 or 3 element.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
<funcdef>text <function>ST_AsGML</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGML</function></funcdef>
<paramdef><type>geography </type> <parameter>g1</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGML</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>precision</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGML</function></funcdef>
<paramdef><type>geography </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>precision</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGML</function></funcdef>
<paramdef><type>integer </type> <parameter>version</parameter></paramdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGML</function></funcdef>
<paramdef><type>integer </type> <parameter>version</parameter></paramdef>
<paramdef><type>geography </type> <parameter>g1</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGML</function></funcdef>
<paramdef><type>integer </type> <parameter>version</parameter></paramdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>precision</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGML</function></funcdef>
<paramdef><type>integer </type> <parameter>version</parameter></paramdef>
<paramdef><type>geography </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>precision</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGML</function></funcdef>
<paramdef><type>integer </type> <parameter>version</parameter></paramdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>precision</parameter></paramdef>
<paramdef><type>integer </type> <parameter>options</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsGML</function></funcdef>
<paramdef><type>integer </type> <parameter>version</parameter></paramdef>
<paramdef><type>geography </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>precision</parameter></paramdef>
<paramdef><type>integer </type> <parameter>options</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsection>
<title>Description</title>
<para>Return the geometry as a Geography Markup Language (GML) element. The version parameter,
if specified, may be either 2 or 3. If no version parameter is
specified then the default is assumed to be 2. The third argument
may be used to reduce the maximum number of decimal places
used in output (defaults to 15).</para>
<para>GML 2 refer to 2.1.2 version, GML 3 to 3.1.1 version</para>
<para>The last 'options' argument is a bitfield. It could be used to define CRS output type
in GML output, and to declare data as lat/lon:
<itemizedlist>
<listitem>
<para>0: GML Short CRS (e.g EPSG:4326), default value</para>
</listitem>
<listitem>
<para>1: GML Long CRS (e.g urn:ogc:def:crs:EPSG:4326)</para>
</listitem>
<listitem>
<para>16: Declare that datas are lat/lon (e.g srid=4326). Default is to assume that data are planars. This option is usefull for GML 3.1.1 output only, related to axis order.</para>
</listitem>
</itemizedlist>
</para>
<!-- TODO: Itemize defaults for each function -->
<note>
<para>Availability: 1.3.2</para>
<para>Availability: 1.5.0 geography support was introduced.</para>
</note>
<para>&Z_support;</para>
</refsection>
<refsection>
<title>Examples</title>
<programlisting><![CDATA[SELECT ST_AsGML(ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326));
st_asgml
--------
<gml:Polygon srsName="EPSG:4326"><gml:outerBoundaryIs><gml:LinearRing><gml:coordinates>0,0 0,1 1,1 1,0 0,0</gml:coordinates></gml:LinearRing></gml:outerBoundaryIs></gml:Polygon>]]>
</programlisting>
<programlisting><![CDATA[SELECT ST_AsGML(3, ST_GeomFromText('POINT(5.234234233242 6.34534534534)',4326), 5, 17);
st_asgml
--------
<gml:Point srsName="urn:ogc:def:crs:EPSG:4326"><gml:pos>6.34535 5.23423</gml:pos></gml:Point>]]>
</programlisting>
</refsection>
<!-- Optionally add a "See Also" section -->
<refsection>
<title>See Also</title>
<para><xref linkend="ST_GeomFromGML" /></para>
</refsection>
</refentry>
<refentry id="ST_AsHEXEWKB">
<refnamediv>
<refname>ST_AsHEXEWKB</refname>
<refpurpose>Returns a Geometry in HEXEWKB format (as text) using either
little-endian (NDR) or big-endian (XDR) encoding.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
<funcdef>text <function>ST_AsHEXEWKB</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
<paramdef><type>text </type> <parameter>NDRorXDR</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsHEXEWKB</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsection>
<title>Description</title>
<para>Returns a Geometry in HEXEWKB format (as text) using either
little-endian (NDR) or big-endian (XDR) encoding. If no encoding is specified, then NDR is used.</para>
<note>
<para>Availability: 1.2.2</para>
</note>
<para>&Z_support;</para>
<para>&curve_support;</para>
</refsection>
<refsection>
<title>Examples</title>
<programlisting>SELECT ST_AsHEXEWKB(ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326));
which gives same answer as
SELECT ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326)::text;
st_ashexewkb
--------
0103000020E6100000010000000500
00000000000000000000000000000000
00000000000000000000000000000000F03F
000000000000F03F000000000000F03F000000000000F03
F000000000000000000000000000000000000000000000000</programlisting>
</refsection>
</refentry>
<refentry id="ST_AsKML">
<refnamediv>
<refname>ST_AsKML</refname>
<refpurpose>Return the geometry as a KML element. Several variants. Default version=2, default precision=15</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
<funcdef>text <function>ST_AsKML</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsKML</function></funcdef>
<paramdef><type>geography </type> <parameter>g1</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsKML</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>precision</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsKML</function></funcdef>
<paramdef><type>geography </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>precision</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsKML</function></funcdef>
<paramdef><type>integer </type> <parameter>version</parameter></paramdef>
<paramdef><type>geometry </type> <parameter>geom1</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsKML</function></funcdef>
<paramdef><type>integer </type> <parameter>version</parameter></paramdef>
<paramdef><type>geography </type> <parameter>geom1</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsKML</function></funcdef>
<paramdef><type>integer </type> <parameter>version</parameter></paramdef>
<paramdef><type>geometry </type> <parameter>geom1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>precision</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsKML</function></funcdef>
<paramdef><type>integer </type> <parameter>version</parameter></paramdef>
<paramdef><type>geography </type> <parameter>geom1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>precision</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsection>
<title>Description</title>
<para>Return the geometry as a Keyhole Markup Language (KML) element. There are several variants of this function.
maximum number of decimal places used in
output (defaults to 15) and version default to 2.</para>
<para>Version 1: ST_AsKML(geom) / version=2 precision=15</para>
<para>Version 2: ST_AsKML(geom, max_sig_digits) / version=2 </para>
<para>Version 3: ST_AsKML(version, geom) / precision=15 </para>
<para>Version 4: ST_AsKML(version, geom, precision) </para>
<note>
<para>Requires PostGIS be compiled with Proj support. Use <xref linkend="PostGIS_Full_Version" /> to confirm you have proj support compiled in.</para>
</note>
<note>
<para>Availability: 1.2.2 - later variants that include version param came in 1.3.2</para>
</note>
<note>
<para>AsKML output will not work with geometries that do not have an SRID</para>
</note>
<para>&Z_support;</para>
</refsection>
<refsection>
<title>Examples</title>
<programlisting><![CDATA[SELECT ST_AsKML(ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326));
st_askml
--------
<Polygon><outerBoundaryIs><LinearRing><coordinates>0,0 0,1 1,1 1,0 0,0</coordinates></LinearRing></outerBoundaryIs></Polygon>
--3d linestring
SELECT ST_AsKML('SRID=4326;LINESTRING(1 2 3, 4 5 6)');
<LineString><coordinates>1,2,3 4,5,6</coordinates></LineString>
]]>
</programlisting>
</refsection>
<refsection>
<title>See Also</title>
<para><xref linkend="ST_AsSVG" />, <xref linkend="ST_AsGML" /></para>
</refsection>
</refentry>
<refentry id="ST_AsSVG">
<refnamediv>
<refname>ST_AsSVG</refname>
<refpurpose>Returns a Geometry in SVG path data given a geometry or geography object.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
<funcdef>text <function>ST_AsSVG</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsSVG</function></funcdef>
<paramdef><type>geography </type> <parameter>g1</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsSVG</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>rel</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsSVG</function></funcdef>
<paramdef><type>geography </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>rel</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsSVG</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>rel</parameter></paramdef>
<paramdef><type>integer </type> <parameter>maxdecimaldigits</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsSVG</function></funcdef>
<paramdef><type>geography </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>rel</parameter></paramdef>
<paramdef><type>integer </type> <parameter>maxdecimaldigits</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsection>
<title>Description</title>
<para>Return the geometry as Scalar Vector Graphics (SVG) path data. Use 1 as second
argument to have the path data implemented in terms of relative
moves, the default (or 0) uses absolute moves. Third argument may
be used to reduce the maximum number of decimal digits used in
output (defaults to 15). Point geometries will be rendered as
cx/cy when 'rel' arg is 0, x/y when 'rel' is 1. Multipoint
geometries are delimited by commas (","), GeometryCollection
geometries are delimited by semicolons (";").</para>
<note>
<para>Availability: 1.2.2 . Availability: 1.4.0 Changed in PostGIS 1.4.0 to include L command in absolute path to conform to <ulink
url="http://www.w3.org/TR/SVG/paths.html#PathDataBNF">http://www.w3.org/TR/SVG/paths.html#PathDataBNF</ulink></para>
</note>
</refsection>
<refsection>
<title>Examples</title>
<programlisting>SELECT ST_AsSVG(ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326));
st_assvg
--------
M 0 0 L 0 -1 1 -1 1 0 Z</programlisting>
</refsection>
</refentry>
<refentry id="ST_GeoHash">
<refnamediv>
<refname>ST_GeoHash</refname>
<refpurpose>Return a GeoHash representation (geohash.org) of the geometry.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
<funcdef>text <function>ST_GeoHash</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_GeoHash</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
<paramdef><type>integer </type> <parameter>precision</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsection>
<title>Description</title>
<para>Return a GeoHash representation (geohash.org) of the geometry. A GeoHash encodes a point into a text form that is sortable and searchable based on prefixing. A shorter GeoHash is a less precise representation of a point. It can also be thought of as a box, that contains the actual point.</para>
<para>The one-parameter variant of ST_GeoHash returns a GeoHash based on the input geometry type. Points return a GeoHash with 20 characters of precision (about enough to hold the full double precision of the input). Other types return a GeoHash with a variable amount of precision, based on the size of the feature. Larger features are represented with less precision, smaller features with more precision. The idea is that the box implied by the GeoHash will always contain the input feature.</para>
<para>The two-parameter variant of ST_GeoHash returns a GeoHash with a requested precision. For non-points, the starting point of the calculation is the center of the bounding box of the geometry.</para>
<para>Availability: 1.4.0</para>
<note>
<para>ST_GeoHash will not work with geometries that are not in geographic (lon/lat) coordinates.</para>
</note>
<para>&curve_support;</para>
</refsection>
<refsection>
<title>Examples</title>
<programlisting><![CDATA[SELECT ST_GeoHash(ST_SetSRID(ST_MakePoint(-126,48),4326));
st_geohash
----------------------
c0w3hf1s70w3hf1s70w3
SELECT ST_GeoHash(ST_SetSRID(ST_MakePoint(-126,48),4326),5);
st_geohash
------------
c0w3h
]]>
</programlisting>
</refsection>
<refsection>
<title>See Also</title>
<para></para>
</refsection>
</refentry>
<refentry id="ST_AsText">
<refnamediv>
<refname>ST_AsText</refname>
<refpurpose>Return the Well-Known Text (WKT) representation of the geometry/geography without SRID metadata.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
<funcdef>text <function>ST_AsText</function></funcdef>
<paramdef><type>geometry </type> <parameter>g1</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>text <function>ST_AsText</function></funcdef>
<paramdef><type>geography </type> <parameter>g1</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsection>
<title>Description</title>
<para>Returns the Well-Known Text representation of the geometry/geography.</para>
<note>
<para>The WKT spec does not include the SRID. To get the SRID as part of the data, use the non-standard
PostGIS <xref linkend="ST_AsEWKT" /></para>
</note>
<para><inlinegraphic fileref="images/warning.png" />
WKT format does not maintain precision so to prevent floating truncation, use ST_AsBinary or ST_AsEWKB format for transport.
</para>
<note>
<para>ST_AsText is the reverse of <xref linkend="ST_GeomFromText" />. Use <xref linkend="ST_GeomFromText" /> to convert to a postgis geometry from ST_AsText representation.</para>
</note>
<para>Availability: 1.5 - support for geography was introduced.</para>
<para>&sfs_compliant; s2.1.1.1</para>
<para>&sqlmm_compliant; SQL-MM 3: 5.1.25</para>
<para>&curve_support;</para>
</refsection>
<refsection>
<title>Examples</title>
<programlisting>SELECT ST_AsText('01030000000100000005000000000000000000
000000000000000000000000000000000000000000000000
F03F000000000000F03F000000000000F03F000000000000F03
F000000000000000000000000000000000000000000000000');
st_astext
--------------------------------
POLYGON((0 0,0 1,1 1,1 0,0 0))
(1 row)</programlisting>
</refsection>
<!-- Optionally add a "See Also" section -->
<refsection>
<title>See Also</title>
<para><xref linkend="ST_AsBinary" />, <xref linkend="ST_AsEWKB" />, <xref linkend="ST_AsEWKT" />, <xref linkend="ST_GeomFromText" /></para>
</refsection>
</refentry>
</sect1>
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