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

ST_ClusterWithinWin is a window function that returns an integer for each input geometry, where the integer the cluster number the geometry is a member of. Clusters represent a set of input geometries separated by no more than the specified distance. (Distances are Cartesian distances in the units of the SRID.)

ST_ClusterWithinWin is equivalent to running ST_ClusterDBSCAN with a `minpoints` of zero.

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

        

See Also

ST_ClusterDBSCAN, ST_ClusterKMeans, ST_ClusterIntersectingWin, ST_ClusterWithin, ST_ClusterIntersecting