This topic describes the ST_Centroid function. This function calculates the center of a geometry object or geography object.

Syntax

geometry  ST_Centroid(geometry  g1);
geography  ST_Centroid(geography  g1 , boolean  useSpheroid);

Parameters

Parameter Description
g1 The geometry object or geography object that you want to specify.
useSpheroid Specifies whether to use an ellipsoid. This parameter is valid if you specify a geography object. Default value: True.

Examples

  • Calculate the center of a MultiPoint object.
    SELECT ST_AsText(ST_Centroid('MULTIPOINT(1 1,-1 -1)'::geometry));
 st_astext
------------
 POINT(0 0)
(1 row)
  • Calculate the center of a LineString object.
    SELECT ST_AsText(ST_Centroid('LINESTRING(0 0,0 1,1 2)'::geometry));
                 st_astext
-------------------------------------------
 POINT(0.292893218813453 1.08578643762691)
(1 row)