This topic describes the ST_BuildArea function. This function creates an areal geometry object formed by the constituent lines of the input geometry object.

Syntax

geometry  ST_BuildArea(geometry  a);

Parameters

Parameter Description
a The geometry object that you want to specify.

Description

  • This function supports LineString objects, MultiLineString objects, polygon objects, MultiPolygon objects, and GeometryCollection objects.
  • This function assumes all inner geometry objects represent holes.
  • This function returns a polygon object or MultiPolygon object. If the constituent lines of the input geometry object cannot form a polygon object, the ST_BuildArea function returns null.

Examples

Results returned by using the default parameter settings:
SELECT ST_AsText(ST_BuildArea('MultiLineString((0 0,0 1),(0 1,1 1),(1 1,0 0))'::geometry));
         st_astext
----------------------------
 POLYGON((0 0,0 1,1 1,0 0))
(1 row)