Opened 3 years ago

Closed 3 years ago

#3572 closed defect (fixed)

ST_ClusterDBSCAN shouldn't join clusters by their borders

Reported by: dbaston Owned by: dbaston
Priority: high Milestone: PostGIS 2.3.0
Component: postgis Version: trunk
Keywords: Cc:

Description

In the DBSCAN algorithm, elements of a cluster are either

  • "core geometries", which are within eps distance of minPoints other geometries, or
  • "border geometries", which are within eps distance of a core geometry

This leads to a situation where a (border) geometry g may not be within eps distance of minPoints other geometries, but is within eps distance of core geometries in two or more different clusters A, B, .... etc. In this case, rather than merging clusters A and B into a single cluster, g should be assigned arbitrarily but deterministically to either A or B, which should remain separate.

Change History (1)

comment:1 Changed 3 years ago by dbaston

Resolution: fixed
Status: newclosed

Applied changes to trunk at r14934

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