Description

Returns the Well-Known Text representation of the geometry/geography. Optional argument may be used to reduce the maximum number of decimal digits after floating point used in output (defaults to 15).

	The WKT spec does not include the SRID. To get the SRID as part of the data, use the non-standard PostGIS ST_AsEWKT

WKT format does not maintain precision so to prevent floating truncation, use ST_AsBinary or ST_AsEWKB format for transport.

	ST_AsText is the reverse of ST_GeomFromText. Use ST_GeomFromText to convert to a postgis geometry from ST_AsText representation.

Availability: 1.5 - support for geography was introduced.

Enhanced: 2.5 - optional parameter precision introduced.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.1

This method implements the SQL/MM specification. SQL-MM 3: 5.1.25

This method supports Circular Strings and Curves

Examples

SELECT ST_AsText('01030000000100000005000000000000000000
000000000000000000000000000000000000000000000000
F03F000000000000F03F000000000000F03F000000000000F03
F000000000000000000000000000000000000000000000000');

		   st_astext
--------------------------------
 POLYGON((0 0,0 1,1 1,1 0,0 0))
(1 row)

Providing the precision is optional.

SELECT ST_AsText(GeomFromEWKT('SRID=4326;POINT(111.1111111 1.1111111)'))
          st_astext
------------------------------
 POINT(111.1111111 1.1111111)
(1 row)

SELECT ST_AsText(GeomFromEWKT('SRID=4326;POINT(111.1111111 1.1111111)'),2)
st_astext
--------------------
POINT(111.11 1.11)
(1 row)

See Also

ST_AsBinary, ST_AsEWKB, ST_AsEWKT, ST_GeomFromText