This topic describes the ST_AsTWKB function. This function returns the Tiny Well-Known Binary (TWKB) string that represents one or more geometry objects.

Syntax

bytea  ST_AsTWKB(geometry  g1 , integer  decimaldigitsXY , integer  decimaldigitsZ , integer  decimaldigitsM , boolean  includeSizes , boolean  includeBoundingBoxes);
bytea  ST_AsTWKB(geometry[]  geometries , bigint[]  uniqueIds , integer  decimaldigitsXy , integer  decimaldigitsZ , integer  decimaldigitsM , boolean  includeSizes , boolean  includeBoundingBoxes);

Parameters

Parameter Description
g1 The geometry object whose TWKB representation you want to obtain.
decimaldigitsXy The number of decimal places that you want to retain in the x and y coordinates. Default value: 0.
decimaldigitsZ The number of decimal places that you want to retain in the z coordinate. Default value: 0.
decimaldigitsM The number of decimal places that you want to retain in the m coordinate. Default value: 0.
includeSizes Specifies whether to return the size of the geometry object. Default value: false.
includeBoundingBoxes Specifies whether to return the bounding box of the geometry object. Default value: false.
geometries An array that consists of the geometry objects whose TWKB representation you want to obtain.
uniqueIds An array that consists of the unique identifiers of the geometry objects whose TWKB representation you want to obtain.

Examples

SELECT ST_AsTWKB(ST_GeomFromText('POINT(116 40)',4326));
       st_astwkb
------------------------
 \xa1008082880b80a4e803
(1 row)