ST_GEOMETRYFROMTEXT

描述

将一个 WKT（Well Known Text）转化为对应的内存的几何形式

别名

ST_GEOMFROMTEXT

语法

ST_GEOMETRYFROMTEXT( <wkt>)

参数

参数	说明
`<wkt>`	图形的内存形式

支持的WKT格式:

POINT - 空间中的单个点
LINESTRING - 连接的线段序列
POLYGON - 由一个或多个环定义的封闭区域, 要求至少有三个不同的点且首尾闭合
MULTIPOLYGON - 多边形的集合, 要求多边形之间仅能存在有限个离散点的接触

:::info 备注从 Apache Doris 2.1.10 开始支持 MULTIPOLYGON 格式解析 :::

返回值

WKB 的对应的几何存储形式

当输入的 WKT 格式不符合规范或输入为 NULL 时返回 NULL。

举例

-- POINT 样例
SELECT ST_AsText(ST_GeometryFromText("POINT (1 1)"));

+-----------------------------------------------+
| ST_AsText(ST_GeometryFromText("POINT (1 1)")) |
+-----------------------------------------------+
| POINT (1 1)                                   |
+-----------------------------------------------+

-- POINT 不合法样例(端点过多)
SELECT ST_AsText(ST_GeometryFromText("POINT (1 1, 2 2)"));

+----------------------------------------------------+
| ST_AsText(ST_GeometryFromText("POINT (1 1, 2 2)")) |
+----------------------------------------------------+
| NULL                                               |
+----------------------------------------------------+

-- LINESTRING 样例
SELECT ST_AsText(ST_GeometryFromText("LINESTRING (1 1, 2 2)"));

+---------------------------------------------------------+
| st_astext(st_geometryfromtext('LINESTRING (1 1, 2 2)')) |
+---------------------------------------------------------+
| LINESTRING (1 1, 2 2)                                   |
+---------------------------------------------------------+

-- LINESTRING 不合法样例(端点过少)
SELECT ST_AsText(ST_GeometryFromText("LINESTRING (1 1)"));

+----------------------------------------------------+
| ST_AsText(ST_GeometryFromText("LINESTRING (1 1)")) |
+----------------------------------------------------+
| NULL                                               |
+----------------------------------------------------+

-- POLYGON 样例
SELECT ST_AsText(ST_GeometryFromText("POLYGON ((0 0, 1 0, 1 1, 0 1, 0 0))"));

+-----------------------------------------------------------------------+
| ST_AsText(ST_GeometryFromText("POLYGON ((0 0, 1 0, 1 1, 0 1, 0 0))")) |
+-----------------------------------------------------------------------+
| POLYGON ((0 0, 1 0, 1 1, 0 1, 0 0))                                   |
+-----------------------------------------------------------------------+

-- POLYGON 不合法样例(首尾不闭合)
SELECT ST_AsText(ST_GeometryFromText("POLYGON ((0 0, 1 0, 1 1, 0 1))"));

+------------------------------------------------------------------+
| ST_AsText(ST_GeometryFromText("POLYGON ((0 0, 1 0, 1 1, 0 1))")) |
+------------------------------------------------------------------+
| NULL                                                             |
+------------------------------------------------------------------+

-- POLYGON 不合法样例(端点过少)
SELECT ST_AsText(ST_GeometryFromText("POLYGON ((0 0, 1 0, 0 0))"));

+-------------------------------------------------------------+
| ST_AsText(ST_GeometryFromText("POLYGON ((0 0, 1 0, 0 0))")) |
+-------------------------------------------------------------+
| NULL                                                        |
+-------------------------------------------------------------+

-- MULTIPOLYGON 样例
SELECT ST_AsText(ST_GeometryFromText("MULTIPOLYGON (((0 0, 1 0, 1 1, 0 1, 0 0)), ((2 2, 3 2, 3 3, 2 3, 2 2)))"));

+-----------------------------------------------------------------------------------------------------------+
| ST_AsText(ST_GeometryFromText("MULTIPOLYGON (((0 0, 1 0, 1 1, 0 1, 0 0)), ((2 2, 3 2, 3 3, 2 3, 2 2)))")) |
+-----------------------------------------------------------------------------------------------------------+
| MULTIPOLYGON (((0 0, 1 0, 1 1, 0 1, 0 0)), ((2 2, 3 2, 3 3, 2 3, 2 2)))                                   |
+-----------------------------------------------------------------------------------------------------------+

-- MULTIPOLYGON 样例(仅有有限个离散点接触)
SELECT ST_AsText(ST_GeometryFromText("MULTIPOLYGON (((0 0, 10 0, 10 10, 0 10, 0 0), (4 4, 6 4, 6 6, 4 6, 4 4)), ((4 5, 5 4, 6 5, 5 6, 4 5)))"));

+------------------------------------------------------------------------------------------------------------------------------------------+
| ST_AsText(ST_GeometryFromText("MULTIPOLYGON (((0 0, 10 0, 10 10, 0 10, 0 0), (4 4, 6 4, 6 6, 4 6, 4 4)), ((4 5, 5 4, 6 5, 5 6, 4 5)))")) |
+------------------------------------------------------------------------------------------------------------------------------------------+
| MULTIPOLYGON (((0 0, 10 0, 10 10, 0 10, 0 0), (4 4, 6 4, 6 6, 4 6, 4 4)), ((4 5, 5 4, 6 5, 5 6, 4 5)))                                   |
+------------------------------------------------------------------------------------------------------------------------------------------+

-- MULTIPOLYGON 不合法样例(存在重叠部分)
SELECT ST_AsText(ST_GeometryFromText("MULTIPOLYGON (((0 0, 10 0, 10 10, 0 10, 0 0)), ((10 0, 20 0, 20 10, 10 10, 10 0)))"));

+----------------------------------------------------------------------------------------------------------------------+
| ST_AsText(ST_GeometryFromText("MULTIPOLYGON (((0 0, 10 0, 10 10, 0 10, 0 0)), ((10 0, 20 0, 20 10, 10 10, 10 0)))")) |
+----------------------------------------------------------------------------------------------------------------------+
| NULL                                                                                                                 |
+----------------------------------------------------------------------------------------------------------------------+

-- 输入 NULL
SELECT ST_AsText(ST_GeometryFromText(NULL));

+--------------------------------------+
| ST_AsText(ST_GeometryFromText(NULL)) |
+--------------------------------------+
| NULL                                 |
+--------------------------------------+

ST_DISTANCE_SPHERE ST_GEOMETRYFROMWKB