#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 mdavis): Now that I've looked at the data in this test case, I can see that this dataset is absolutely a worst-case scenario for union. The reason is that there are so many intersections between the lines, it is going to produce on the order of O(n^2) node points. This means the noding process has to run in slow O(n^2) time. Also, memory usage is going to be very large. So this is an example of where using Union within the Concave Hull algorithm is not a good idea. -- Ticket URL: <https://trac.osgeo.org/geos/ticket/982#comment:17> GEOS <http://trac.osgeo.org/geos> GEOS (Geometry Engine - Open Source) is a C++ port of the Java Topology Suite (JTS).
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