ST_ClusterWithinWin
Name
ST_ClusterWithinWin — Window function that returns a cluster id for each input geometry, clustering using separation distance.
Synopsis
integer
ST_ClusterWithinWin
(
geometry winset
geom
, float8
distance
)
;
Description
A window function that returns a cluster number for each input geometry.
Clustering partitions the geometries into sets
in which each geometry is within the specified
distance
of at least one other geometry in the same cluster.
Distances are Cartesian distances in the units of the SRID.
ST_ClusterWithinWin is equivalent to running
ST_ClusterDBSCAN
with
minpoints := 0
.
Availability: 3.4.0
This method supports Circular Strings and Curves.
Examples
WITH testdata AS (
SELECT id, geom::geometry FROM (
VALUES (1, 'LINESTRING (0 0, 1 1)'),
(2, 'LINESTRING (5 5, 4 4)'),
(3, 'LINESTRING (6 6, 7 7)'),
(4, 'LINESTRING (0 0, -1 -1)'),
(5, 'POLYGON ((0 0, 4 0, 4 4, 0 4, 0 0))')) AS t(id, geom)
)
SELECT id,
ST_AsText(geom),
ST_ClusterWithinWin(geom, 1.4) OVER () AS cluster
FROM testdata;
id | st_astext | cluster
----+--------------------------------+---------
1 | LINESTRING(0 0,1 1) | 0
2 | LINESTRING(5 5,4 4) | 0
3 | LINESTRING(6 6,7 7) | 1
4 | LINESTRING(0 0,-1 -1) | 0
5 | POLYGON((0 0,4 0,4 4,0 4,0 0)) | 0