ST_Centroid(geometry) 函數(shù)

ST_Centroid(geometry) 函數(shù) -= 作用：

獲取幾何對象的中心點

語法：

ST_Centroid (geometry Data Type)

返回類型：

PostGis return type: geometry

Examples: 例 1：

SELECT ST_Centroid('MULTIPOINT ( -1 0, -1 2, -1 3, -1 4, -1 7, 0 1, 0 3, 1 1, 2 0, 6 0, 7 8, 9 8, 10 6 )');


------------------------------------------
010100000062277662277602406227766227760A40

例 2：

SELECT ST_AsText(ST_Centroid('MULTIPOINT ( -1 0, -1 2, -1 3, -1 4, -1 7, 0 1, 0 3, 1 1, 2 0, 6 0, 7 8, 9 8, 10 6 )'));


------------------------------------------
POINT(2.30769230769231 3.30769230769231)
(1 row)

例 3：

SELECT st_asgeojson(ST_Centroid('MULTIPOINT ( -1 0, -1 2, -1 3, -1 4, -1 7, 0 1, 0 3, 1 1, 2 0, 6 0, 7 8, 9 8, 10 6 )'));


---------------------------------------
{"type":"Point","coordinates":[2.30769230769231,3.30769230769231]}

參考文獻：

1.https://docs.microsoft.com/zh-cn/sql/t-sql/spatial-geometry/stcentroid-geometry-data-type

2.http://www.postgis.net/docs/ST_Centroid.html