#743: Number of buffered points not always a multiple of quadrantSegments -----------------------+-------------------------- Reporter: mwtoews | Owner: geos-devel@… Type: defect | Status: new Priority: major | Milestone: 3.5.1 Component: Default | Version: 3.5.0 Severity: Annoyance | Keywords: -----------------------+-------------------------- Using Buffer with quadrantSegments, it is expected that the number of unique points is quadrantSegments * 4. However, for some quadrantSegments there is an extra point that is a near duplicate of the last.
For example quadrantSegments = 13, using either Shapely or PostGIS: {{{ -- PostGIS SELECT ST_AsText(ST_Buffer(ST_MakePoint(0, 0), 1.0, 13)); # Shapely from shapely.geometry import Point Point(0, 0).buffer(1.0, 13).wkt }}} results with 53 unique points (or 54 with repeat last) `POLYGON((1 0,...,1 1.44557759859665e-14,1 0))`, where the second last is within machine epsilon distance of the last coordinate. This example for quadrantSegments = 13 should have 52 unique points, or 53 points for a closed polygon. This is not an isolated case for quadrantSegments = 13; same also for: 13, 15, 16, 17, 20, 22, 25, 26, 28, 31, 32, 38, 39, 42, 43, 45, 46, 47, 49, 50, 51, 53, 54, 56, 57, 62, 64, 67, 68, 71, 75, 76, 78, 81, 83, 84, 85, 89, 90, ... It seems there are no issues with JTS on this issue. -- Ticket URL: <https://trac.osgeo.org/geos/ticket/743> GEOS <http://trac.osgeo.org/geos> GEOS (Geometry Engine - Open Source) is a C++ port of the Java Topology Suite (JTS). _______________________________________________ geos-devel mailing list geos-devel@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/geos-devel