Name
ST_GeomFromText — 从已知的文本表示 (WKT) 返回指定的 ST_Geometry 值。
Synopsis
geometry ST_GeomFromText(text WKT);
geometry ST_GeomFromText(text WKT, integer srid);
描述
从 OGC 已知的文本表示（WKT）构造 PostGIS ST_Geometry 对象。
![[Note]](../images/note.png)
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ST_GeomFromText 函数有两种变体。 第一个不采用 SRID，并返回没有定义空间参考系统 (SRID=0) 的几何图形。 第二个将 SRID 作为第二个参数，并返回一个几何图形，该几何图形包含此 SRID 作为其元数据的一部分。 |
此方法实现了 SQL 1.1 的 OGC 简单功能规范。 s3.2.6.2 - 可选参数 SRID 用于规范一致性。
该方法实现了SQL/MM规范。 SQL-MM 3: 5.1.40
此方法支持圆形字符串和曲线。
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它不符合 OGC，但ST_MakePoint比 ST_GeomFromText 和 ST_PointFromText 更快。 另一个优点是，如果使用数字作为坐标值，则更容易。 另一种选择是ST_Point，它在速度方面与ST_MakePoint相似，并且符合 OGC 标准，但仅支持 2D 点。 |
![[Warning]](../images/warning.png)
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更改：2.0.0 在 PostGIS 的早期版本中，允许 ST_GeomFromText('GEOMETRYCOLLECTION(EMPTY)') 。 为了更好地符合 SQL/MM 标准，这在 PostGIS 2.0.0 中现在是非法的。 现在应该写成 ST_GeomFromText('GEOMETRYCOLLECTION EMPTY') |
示例
SELECT ST_GeomFromText('LINESTRING(-71.160281 42.258729,-71.160837 42.259113,-71.161144 42.25932)');
SELECT ST_GeomFromText('LINESTRING(-71.160281 42.258729,-71.160837 42.259113,-71.161144 42.25932)',4269);
SELECT ST_GeomFromText('MULTILINESTRING((-71.160281 42.258729,-71.160837 42.259113,-71.161144 42.25932))');
SELECT ST_GeomFromText('POINT(-71.064544 42.28787)');
SELECT ST_GeomFromText('POLYGON((-71.1776585052917 42.3902909739571,-71.1776820268866 42.3903701743239,
-71.1776063012595 42.3903825660754,-71.1775826583081 42.3903033653531,-71.1776585052917 42.3902909739571))');
SELECT ST_GeomFromText('MULTIPOLYGON(((-71.1031880899493 42.3152774590236,
-71.1031627617667 42.3152960829043,-71.102923838298 42.3149156848307,
-71.1023097974109 42.3151969047397,-71.1019285062273 42.3147384934248,
-71.102505233663 42.3144722937587,-71.10277487471 42.3141658254797,
-71.103113945163 42.3142739188902,-71.10324876416 42.31402489987,
-71.1033002961013 42.3140393340215,-71.1033488797549 42.3139495090772,
-71.103396240451 42.3138632439557,-71.1041521907712 42.3141153348029,
-71.1041411411543 42.3141545014533,-71.1041287795912 42.3142114839058,
-71.1041188134329 42.3142693656241,-71.1041112482575 42.3143272556118,
-71.1041072845732 42.3143851580048,-71.1041057218871 42.3144430686681,
-71.1041065602059 42.3145009876017,-71.1041097995362 42.3145589148055,
-71.1041166403905 42.3146168544148,-71.1041258822717 42.3146748022936,
-71.1041375307579 42.3147318674446,-71.1041492906949 42.3147711126569,
-71.1041598612795 42.314808571739,-71.1042515013869 42.3151287620809,
-71.1041173835118 42.3150739481917,-71.1040809891419 42.3151344119048,
-71.1040438678912 42.3151191367447,-71.1040194562988 42.3151832057859,
-71.1038734225584 42.3151140942995,-71.1038446938243 42.3151006300338,
-71.1038315271889 42.315094347535,-71.1037393329282 42.315054824985,
-71.1035447555574 42.3152608696313,-71.1033436658644 42.3151648370544,
-71.1032580383161 42.3152269126061,-71.103223066939 42.3152517403219,
-71.1031880899493 42.3152774590236)),
((-71.1043632495873 42.315113108546,-71.1043583974082 42.3151211109857,
-71.1043443253471 42.3150676015829,-71.1043850704575 42.3150793250568,-71.1043632495873 42.315113108546)))',4326);
SELECT ST_GeomFromText('CIRCULARSTRING(220268 150415,220227 150505,220227 150406)');