Functions That Create Geometry Values from WKT Values Functions in this section detect arguments in either Cartesian or geographic spatial reference systems (SRSs), and return results appropriate to the SRS. ST_GeomFromText()  accepts a WKT value of any geometry type as its first argument. Other functions provide type-specific construction functions for construction of geometry values of each geometry type. Functions such as  ST_MPointFromText()  and  ST_GeomFromText()  that accept WKT-format representations of  MultiPoint  values permit individual points within values to be surrounded by parentheses. For example, both of the following function calls are valid: ST_MPointFromText(’MULTIPOINT (1 1, 2 2, 3 3)’) ST_MPointFromText(’MULTIPOINT ((1 1), (2 2), (3 3))’) Functions such as  ST_GeomFromText()  that accept WKT geometry collection arguments understand both OpenGIS  ’GEOMETRYCOLLECTION EMPTY’  standard syntax and MySQL ’GEOMETRYCOLLECTION()’  nonstandard syntax. Functions such as  ST_AsWKT()  that produce WKT values produce  ’GEOMETRYCOLLECTION EMPTY’  standard syntax: mysql>  SET @s1 = ST_GeomFromText(’GEOMETRYCOLLECTION()’); mysql>  SET @s2 = ST_GeomFromText(’GEOMETRYCOLLECTION EMPTY’); mysql>  SELECT ST_AsWKT(@s1), ST_AsWKT(@s2); +--------------------------+--------------------------+ | ST_AsWKT(@s1) | ST_AsWKT(@s2) | +--------------------------+--------------------------+ | GEOMETRYCOLLECTION EMPTY | GEOMETRYCOLLECTION EMPTY | +--------------------------+--------------------------+ Unless otherwise specified, functions in this section handle their geometry arguments as follows: •If any geometry argument is  NULL  or is not a syntactically well-formed geometry, or if the SRID argument is  NULL , the return value is  NULL . •By default, geographic coordinates (latitude, longitude) are interpreted as in the order specified by the spatial reference system of geometry arguments. An optional  options  argument may be given to override the default axis order.  options  consists of a list of comma-separated  key = value . The only permitted  key  value is  axis-order , with permitted values of  lat-long ,  long-lat  and  srid- defined  (the default). If the  options  argument is  NULL , the return value is  NULL . If the  options  argument is invalid, an error occurs to indicate why. •If an SRID argument refers to an undefined spatial reference system (SRS), an  ER_SRS_NOT_FOUND error occurs. •For geographic SRS geometry arguments, if any argument has a longitude or latitude that is out of range, an error occurs: • If a longitude value is not in the range ( − 180, 180], an  ER_LONGITUDE_OUT_OF_RANGE  error occurs. • If a latitude value is not in the range [ − 90, 90], an  ER_LATITUDE_OUT_OF_RANGE  error occurs. Ranges shown are in degrees. If an SRS uses another unit, the range uses the corresponding values in its unit. The exact range limits deviate slightly due to floating-point arithmetic. These functions are available for creating geometries from WKT values: • ST_GeomCollFromText( wkt  [,  srid  [,  options ]]) , ST_GeometryCollectionFromText( wkt  [,  srid  [,  options ]]) , ST_GeomCollFromTxt( wkt  [,  srid  [,  options ]]) 2296