ST_RemovePoint returns a linestring geometry that has the point of the input geometry at an index position removed.
The index is zero-based. The spatial reference system identifier (SRID) of the result is the same as the input geometry. The dimension of the returned geometry is the same as that of the input geometry.
Syntax
ST_RemovePoint(geom, index)
Arguments
- geom
-
A value of data type
GEOMETRYor an expression that evaluates to aGEOMETRYtype. The subtype must beLINESTRING. - index
-
A value of data type
INTEGERthat represents the position of a zero-based index.
Return type
GEOMETRY
If geom or index is null, then null is returned.
If geom is not subtype LINESTRING, then an error is returned.
If index is out of range, then an error is returned. Valid
values for the index position are between 0 and ST_NumPoints(geom) minus 1.
Examples
The following SQL removes the last point in a linestring.
WITH tmp(g) AS (SELECT ST_GeomFromText('LINESTRING(0 0,10 0,10 10,5 5,0 5)',4326))
SELECT ST_AsEWKT(ST_RemovePoint(g, ST_NumPoints(g) - 1)) FROM tmp;
st_asewkt
-----------------------------------------
SRID=4326;LINESTRING(0 0,10 0,10 10,5 5)
