说明

如果几何/地理是 ST_Surface、ST_MultiSurface（多边形、多边形），则返回其二维周长。对于非面几何，返回 0。对于线性几何，使用 ST_Length。对于几何类型，周长测量单位由几何的空间参考系统指定。

对于地理类型，计算使用逆测地问题执行，其中周长单位为米。如果 PostGIS 使用 PROJ 版本 4.8.0 或更高版本编译，则椭球体由 SRID 指定，否则它专用于 WGS84。如果 use_spheroid = false，则计算将近似为球体，而不是椭球体。

当前，这是 ST_Perimeter2D 的别名，但可能会更改以支持更高的维度。

此方法实现了 OGC 针对 SQL 1.1 的简单要素实施规范。

s2.1.5.1

此方法实现了 SQL/MM 规范。

SQL-MM 3: 8.1.3, 9.5.4

可用性 2.0.0：引入了对地理的支持

示例：几何

以英尺为单位返回多边形和多边形的周长。请注意，这是以英尺为单位，因为 EPSG:2249 是马萨诸塞州平面英尺

SELECT ST_Perimeter(ST_GeomFromText('POLYGON((743238 2967416,743238 2967450,743265 2967450,
743265.625 2967416,743238 2967416))', 2249));
st_perimeter
---------
 122.630744000095
(1 row)

SELECT ST_Perimeter(ST_GeomFromText('MULTIPOLYGON(((763104.471273676 2949418.44119003,
763104.477769673 2949418.42538203,
763104.189609677 2949418.22343004,763104.471273676 2949418.44119003)),
((763104.471273676 2949418.44119003,763095.804579742 2949436.33850239,
763086.132105649 2949451.46730207,763078.452329651 2949462.11549407,
763075.354136904 2949466.17407812,763064.362142565 2949477.64291974,
763059.953961626 2949481.28983009,762994.637609571 2949532.04103014,
762990.568508415 2949535.06640477,762986.710889563 2949539.61421415,
763117.237897679 2949709.50493431,763235.236617789 2949617.95619822,
763287.718121842 2949562.20592617,763111.553321674 2949423.91664605,
763104.471273676 2949418.44119003)))', 2249));
st_perimeter
---------
 845.227713366825
(1 row)
			

示例：地理

以米和英尺为单位返回多边形和多边形的周长。请注意，这是地理（WGS 84 长度纬度）

SELECT  ST_Perimeter(geog) As per_meters, ST_Perimeter(geog)/0.3048 As per_ft
FROM ST_GeogFromText('POLYGON((-71.1776848522251 42.3902896512902,-71.1776843766326 42.3903829478009,
-71.1775844305465 42.3903826677917,-71.1775825927231 42.3902893647987,-71.1776848522251 42.3902896512902))') As geog;

   per_meters    |      per_ft
-----------------+------------------
37.3790462565251 | 122.634666195949


-- MultiPolygon example --
SELECT  ST_Perimeter(geog) As per_meters, ST_Perimeter(geog,false) As per_sphere_meters,  ST_Perimeter(geog)/0.3048 As per_ft
FROM ST_GeogFromText('MULTIPOLYGON(((-71.1044543107478 42.340674480411,-71.1044542869917 42.3406744369506,
-71.1044553562977 42.340673886454,-71.1044543107478 42.340674480411)),
((-71.1044543107478 42.340674480411,-71.1044860600303 42.3407237015564,-71.1045215770124 42.3407653385914,
-71.1045498002983 42.3407946553165,-71.1045611902745 42.3408058316308,-71.1046016507427 42.340837442371,
-71.104617893173 42.3408475056957,-71.1048586153981 42.3409875993595,-71.1048736143677 42.3409959528211,
-71.1048878050242 42.3410084812078,-71.1044020965803 42.3414730072048,
-71.1039672113619 42.3412202916693,-71.1037740497748 42.3410666421308,
-71.1044280218456 42.3406894151355,-71.1044543107478 42.340674480411)))') As geog;

    per_meters    | per_sphere_meters |      per_ft
------------------+-------------------+------------------
 257.634283683311 |  257.412311446337 | 845.256836231335
			

另请参阅

ST_GeogFromText、ST_GeomFromText、ST_Length