Alias

SetPoint

Description

Replaces the Nth Point of a LineString or a Polygon for a new Point. N index starts at 0.

If the N index is out of range, or the incoming geometry is not a LineString or a Polygon, the resulting geometry is returned unchanged.

	MultiLineString and MultiPolygon supported GeometryCollection not supported

Coordinate Dimensions

2D	3D	M

Spatial Standards Support

Examples

SELECT ST_AsEWKT(Line) as original,
       ST_AsEWKT(ST_SetPoint(Line,0,Point)) as NewPoint0,
       ST_AsEWKT(ST_SetPoint(Line,1,Point)) as NewPoint1 
FROM (SELECT ST_GeomFromEWKT('LINESTRING (0 0, 10 10, 20 10)') as Line, ST_GeomFromEWKT('POINT (-5 5)') as Point) as foo;

            original            |            newpoint0            |           newpoint1
--------------------------------+---------------------------------+-------------------------------
 LINESTRING (0 0, 10 10, 20 10) | LINESTRING (-5 5, 10 10, 20 10) | LINESTRING (0 0, -5 5, 20 10)


SELECT ST_AsEWKT(ST_SetPoint(ST_GeomFromEWKT('MULTILINESTRING ((0 0, 10 10, 20 10),(30 30, 40 40, 50 40))'),5,ST_GeomFromEWKT('POINT (-5 5)')));
--Result
MULTILINESTRING ((0 0, 10 10, 20 10), (30 30, 40 40, -5 5)) 

--Polygon
SELECT ST_AsEWKT(ST_SetPoint(ST_GeomFromEWKT('POLYGON ((0 0, 0 10, 10 10, 10 0, 0 0))'),2,ST_GeomFromEWKT('POINT (-5 5)')));
--Result
POLYGON ((0 0, 0 10, -5 5, 10 0, 0 0))

--N index out of range
SELECT ST_AsEWKT(ST_SetPoint(ST_GeomFromEWKT('LINESTRING (0 0, 10 10, 20 10)'),5,ST_GeomFromEWKT('POINT (-5 5)')));
--Result
LINESTRING (0 0, 10 10, 20 10)

Related functions

ST_AddPoint