ST_ASBINARY

描述

将一个几何图形转换为标准的 WKB (Well-Known Binary) 二进制表示形式。WKB 是一种用于表示地理空间数据的二进制格式，广泛应用于地理信息系统 (GIS) 中。

目前支持的几何图形类型包括：Point（点）、LineString（线）、Polygon（多边形）

语法

ST_ASBINARY( <geo>)

参数

参数	说明
<geo>	需要转换为 WKB 格式的几何图形对象,包括：Point（点）、LineString（线）、Polygon（多边形）

返回值

返回该几何图形的 WKB 二进制表示，以十六进制字符串形式展示（例如：\x01010000...）。

ST_ASBINARY 存在以下边缘情况：

• 若输入参数为 NULL，返回 NULL。
• 若输入的几何图形类型不支持，返回 NULL。

举例

点对象转换

select ST_AsBinary(st_point(24.7, 56.7));

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

线对象转换

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

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

多边形对象转换

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 |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

不支持的类型MultiPolyGon返回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 输入

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