[geos-devel] [GEOS] #982: Postgis ST_ConcaveHull Runtime GEOS Problem?

GEOS geos-trac at osgeo.org
Sun Aug 25 11:07:08 PDT 2019

#982: Postgis ST_ConcaveHull Runtime GEOS Problem?
 Reporter:  tsw         |       Owner:  geos-devel@…
     Type:  defect      |      Status:  reopened
 Priority:  major       |   Milestone:
Component:  Default     |     Version:  3.7.0
 Severity:  Unassigned  |  Resolution:
 Keywords:              |

Comment (by tsw):

 It may be the concave hull with this data set identified an underlying

 As I don't understand the underlying algorithm however I'll point out a
 few things. If you run the test ST_Concavehull query as it currently
 stands in PostGIS and GEOS and buffer the lines by 10 meters, it is still
 never completes. I'm not sure that indicates a GEOS problem or not.

 Manipulating the _st_concavehull code to remove UnaryUnion fixes the
 performance but then not everything is encapsulated by the hull.

 I'll leave it to you folks to determine the cause and the fix, but wanted
 to provide as much information as possible to help diagnose the cause.

Ticket URL: <https://trac.osgeo.org/geos/ticket/982#comment:14>
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GEOS (Geometry Engine - Open Source) is a C++ port of the Java Topology Suite (JTS).

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