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ST_CENTROID ​

Computes the geometric center (centroid) of a GEOGRAPHY object.

  • For [MULTI]POINT objects, the centroid is the arithmetic mean of the input coordinates
  • For [MULTI]LINESTRING objects, the centroid is calculated using the weighted length of each line segment
  • For [MULTI]POLYGON objects, the centroid is determined based on the area

Note: The centroid is not always guaranteed to be within the original shape

Syntax ​

sql
ST_CENTROID(<input>)

Arguments ​

  • <input>: A GEOGRAPHY value to compute the centroid of

Returns ​

Returns a GEOGRAPHY of subtype ST_Point representing the centroid.

For mixed-dimension input, the result is equal to the centroid of the component shapes of highest dimension (since the lower-dimension shapes contribute zero "weight" to the centroid).

Example ​

sql
SELECT ST_AsText(ST_Centroid('POLYGON((0 0, 2 0, 2 2, 0 2, 0 0))'::GEOGRAPHY));
-- POINT(1 1)