ST_AddPoint - Amazon Redshift
SyntaxArgumentsReturn typeExamples
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ST_AddPoint

ST_AddPoint returns a linestring geometry that is the same as the input geometry with a point added. If an index is provided, then the point is added at the index position. If the index is -1 or not provided, then the point is appended to the linestring.

The index is zero-based. The spatial reference system identifier (SRID) of the result is the same as that of the input geometry.

The dimension of the returned geometry is the same as that of the geom1 value. If geom1 and geom2 have different dimensions, geom2 is projected to the dimension of geom1.

Syntax

ST_AddPoint(geom1, geom2)
ST_AddPoint(geom1, geom2, index)

Arguments

geom1

A value of data type GEOMETRY or an expression that evaluates to a GEOMETRY type. The subtype must be LINESTRING.

geom2

A value of data type GEOMETRY or an expression that evaluates to a GEOMETRY type. The subtype must be POINT. The point can be the empty point.

index

A value of data type INTEGER that represents the position of a zero-based index.

Return type

GEOMETRY

If geom1, geom2, or index is null, then null is returned.

If geom2 is the empty point, then a copy of geom1 is returned.

If geom1 is not a LINESTRING, then an error is returned.

If geom2 is not a POINT, then an error is returned.

If index is out of range, then an error is returned. Valid values for the index position are -1 or a value between 0 and ST_NumPoints(geom1).

Examples

The following SQL adds a point to a linestring to make it a closed linestring. 

WITH tmp(g) AS (SELECT ST_GeomFromText('LINESTRING(0 0,10 0,10 10,5 5,0 5)',4326))
SELECT ST_AsEWKT(ST_AddPoint(g, ST_StartPoint(g))) FROM tmp;

 st_asewkt
------------------------------------------------
 SRID=4326;LINESTRING(0 0,10 0,10 10,5 5,0 5,0 0)

The following SQL adds a point to a specific position 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_AddPoint(g, ST_SetSRID(ST_Point(5, 10), 4326), 3)) FROM tmp;

 st_asewkt
------------------------------------------------
 SRID=4326;LINESTRING(0 0,10 0,10 10,5 10,5 5,0 5)