ST_AsBinary-PolarDB(PolarDB)-阿里云帮助中心

Returns the Well-Known Binary (WKB) representation of a geometry or geography object. The output does not include spatial reference identifier (SRID) metadata.

Syntax

bytea ST_AsBinary(geometry g1);
bytea ST_AsBinary(geometry g1, text NDRorXDR);
bytea ST_AsBinary(geography g1);
bytea ST_AsBinary(geography g1, text NDRorXDR);

Parameters

Parameter	Description
`g1`	The geometry or geography object to convert to WKB.
`NDRorXDR`	The byte order of the output. Valid values: `NDR` (little endian, default) and `XDR` (big endian).

Usage notes

Standard WKB does not include SRID metadata. To get a WKB representation with the SRID embedded, use ST_AsEWKB instead.
Supported geometry types include circular strings, curves, polyhedral surfaces, triangles, triangulated irregular network (TIN) surfaces, and 3D objects.

Examples

Return WKB with the default little endian byte order

SELECT ST_AsBinary(ST_GeomFromText('POLYGON((1 1,1 2,2 2,2 1,1 1))',4326));

                          st_asbinary
---------------------------------------------------------------
 \x01030000000100000005000000000000000000f03f000000000000f03f0
.00000000000f03f0000000000000040000000000000004000000000000000
.400000000000000040000000000000f03f000000000000f03f00000000000
.0f03f
(1 row)

Return WKB with big endian byte order

SELECT ST_AsBinary(ST_GeomFromText('POLYGON((1 1,1 2,2 2,2 1,1 1))',4326),'XDR');

                          st_asbinary
---------------------------------------------------------------
 \x000000000300000001000000053ff00000000000003ff00000000000003
.ff00000000000004000000000000000400000000000000040000000000000
.0040000000000000003ff00000000000003ff00000000000003ff00000000
.00000
(1 row)

What's next

ST_AsEWKB — returns WKB with the SRID included