ST_ASBINARY

Description

Converts a geometric object into a standard WKB (Well-Known Binary) binary representation. WKB is a binary format for representing geospatial data, widely used in Geographic Information Systems (GIS).

Currently supported geometric types include: Point, LineString, and Polygon.

Sytax

ST_ASBINARY( <geo>)

Parameters

Parameter	Description
<geo>	The geometric object to be converted to WKB format, including: Point, LineString, Polygon.）

Retuen value

Returns the WKB binary representation of the geometric object, displayed as a hexadecimal string (e.g., \x01010000...).

ST_ASBINARY has the following edge cases:

• If the input parameter is NULL, returns NULL.
• If the input geometric type is not supported, returns NULL.

Example

Point object conversion

select ST_AsBinary(st_point(24.7, 56.7));

+----------------------------------------------+
| st_asbinary(st_point(24.7, 56.7))            |
+----------------------------------------------+
| \x01010000003333333333b338409a99999999594c40 |
+----------------------------------------------+

LineString object conversion

select ST_AsBinary(ST_GeometryFromText("LINESTRING (1 1, 2 2)"));

+--------------------------------------------------------------------------------------+
| st_asbinary(st_geometryfromtext('LINESTRING (1 1, 2 2)'))                            |
+--------------------------------------------------------------------------------------+
| \x010200000002000000000000000000f03f000000000000f03f00000000000000400000000000000040 |
+--------------------------------------------------------------------------------------+

Polygon object conversion

select ST_AsBinary(ST_Polygon("POLYGON ((114.104486 22.547119,114.093758 22.547753,114.096504 22.532057,114.104229 22.539826,114.106203 22.542680,114.104486 22.547119))"));

+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| st_asbinary(st_polygon('POLYGON ((114.104486 22.547119,114.093758 22.547753,114.096504 22.532057,114.104229 22.539826,114.106203 22.542680,114.104486 22.547119))'))                                                         |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| \x01030000000100000006000000f3380ce6af865c402d05a4fd0f8c364041ef8d2100865c403049658a398c3640b9fb1c1f2d865c409d9b36e334883640de921cb0ab865c40cf876709328a36402cefaa07cc865c407b319413ed8a3640f3380ce6af865c402d05a4fd0f8c3640 |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

Unsupported type (MultiPolygon) returns NULL

mysql> SELECT ST_AsBinary(ST_GeometryFromText("MULTIPOLYGON (((0 0, 1 0, 1 1, 0 1, 0 0)), ((2 2, 3 2, 3 3, 2 3, 2 2)))"));
+-------------------------------------------------------------------------------------------------------------+
| ST_AsBinary(ST_GeometryFromText("MULTIPOLYGON (((0 0, 1 0, 1 1, 0 1, 0 0)), ((2 2, 3 2, 3 3, 2 3, 2 2)))")) |
+-------------------------------------------------------------------------------------------------------------+
| NULL                                                                                                        |
+-------------------------------------------------------------------------------------------------------------+

NULL input

mysql> SELECT ST_AsBinary(NULL);
+-------------------+
| ST_AsBinary(NULL) |
+-------------------+
| NULL              |
+-------------------+