ST_GEOMFROMEWKT

📄字数 1.1K

👁️阅读量 加载中...

功能描述

根据 OGC 扩展已知文本 (EWKT) 表示构造 ST_GEOMETRY 对象。

语法格式

GEOMETRY ST_GEOMFROMEWKT(CLOB EWKT);

参数说明

• EWKT：已知文本或扩展已知文本字符串。

函数返回类型

GEOMETRY 类型

使用说明

1. 该函数支持 3d 并且不会丢失 z-index。
2. 此方法支持圆形字符串和曲线。
3. 该函数支持多面体曲面。
4. 此函数支持三角形和不规则三角网面 (TIN)。

示例

SQL> SELECT TO_CHAR(ST_ASEWKT(ST_GEOMFROMEWKT('SRID=4269;LINESTRING(-71.160281 42.258729,-71.160837 42.259113,-71.161144 42.25932)')));

+-------------------------------------------------------------------------------------+
|                                        EXPR1                                        |
+-------------------------------------------------------------------------------------+
| SRID=4269;LINESTRING(-71.160281 42.258729,-71.160837 42.259113,-71.161144 42.25932) |
+-------------------------------------------------------------------------------------+

SQL> SELECT TO_CHAR(ST_ASTEXT(ST_GEOMFROMEWKT('SRID=4269;POLYGON((-71.1776585052917 42.3902909739571,-71.1776820268866 42.3903701743239,
     -71.1776063012595 42.3903825660754,-71.1775826583081 42.3903033653531,-71.1776585052917 42.3902909739571))')));

+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|                                                                                           EXPR1                                                                                           |
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| POLYGON((-71.1776585052917 42.3902909739571,-71.1776820268866 42.3903701743239,-71.1776063012595 42.3903825660754,-71.1775826583081 42.3903033653531,-71.1776585052917 42.3902909739571)) |
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

-- 3D 圆形字符串
SQL> SELECT TO_CHAR(ST_ASTEXT(ST_GEOMFROMEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)')));

+--------------------------------------------------------------------+
|                               EXPR1                                |
+--------------------------------------------------------------------+
| CIRCULARSTRING Z (220268 150415 1,220227 150505 2,220227 150406 3) |
+--------------------------------------------------------------------+

-- 多面体曲面

SQL> SELECT TO_CHAR(ST_ASTEXT(ST_GEOMFROMEWKT('POLYHEDRALSURFACE(
             ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
             ((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)),
             ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
             ((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
             ((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)),
             ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1))
     )')));

+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|                                                                                                               EXPR1                                                                                                               |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| POLYHEDRALSURFACE Z (((0 0 0,0 0 1,0 1 1,0 1 0,0 0 0)),((0 0 0,0 1 0,1 1 0,1 0 0,0 0 0)),((0 0 0,1 0 0,1 0 1,0 0 1,0 0 0)),((1 1 0,1 1 1,1 0 1,1 0 0,1 1 0)),((0 1 0,0 1 1,1 1 1,1 1 0,0 1 0)),((0 0 1,1 0 1,1 1 1,0 1 1,0 0 1))) |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+