[geos-devel] [GEOS] #859: Voronoi issue

[GEOS]

#859: Voronoi issue
------------------------+--------------------------
 Reporter:  jjgreen     |      Owner:  geos-devel@…
     Type:  defect      |     Status:  new
 Priority:  major       |  Milestone:  3.5.2
Component:  Default     |    Version:  3.5.1
 Severity:  Unassigned  |   Keywords:
------------------------+--------------------------
 OSGEO Voronoi issue

 Further to a posting on the PostGIS mailing list
 in February 2018, this directory contains scripts
 to generate data for the bug report for OSGEO.
 The scripts generating the data can only be used
 against a copy of the seadb DB which is not open
 source, but the `reproduce.sh` script can be used
 (with minimal modifications) to reproduce the issue
 with the CSV file output from the DB.

 For my setup, which is Ubuntu Xenial with PostGIS
 from apt-postgresql.org and

 - POSTGIS="2.3.3 r15473"
 - GEOS="3.5.0-CAPI-1.9.0 r4084"
 - PROJ="Rel. 4.9.2, 08 September 2015"
 - GDAL="GDAL 1.11.3, released 2015/09/16"
 - LIBXML="2.9.3"
 - LIBJSON="0.11.99" RASTER

 the `reproduce.sh` script reports

     CREATE TABLE
     COPY 1322
     CREATE INDEX
     ERROR:  GEOSVoronoiDiagram: TopologyException: Input
         geom 1 is invalid: Self-intersection at or near point
         444332.38647522771 8548816.0569835864 at
         444332.38647522771 8548816.0569835864

 As discussed in the PostGIS forum thread mentioned above, we
 find that `ST_SnapToGrid` with dyadic grid step fixes the
 issue.

 The original data for these points was the EuroROSE project,
 an EU-funded experiment on the feasibility of the use of
 HF-radar for measuring ocean waves, currents and so on. The
 experiment took place at Fedje, Norway in early 2000. More
 details can be found at

     http://wera.cen.uni-hamburg.de/EuroROSE/EuroROSE_Intro.shtml

-- 
Ticket URL: <https://trac.osgeo.org/geos/ticket/859>
GEOS <http://trac.osgeo.org/geos>
GEOS (Geometry Engine - Open Source) is a C++ port of the Java Topology Suite (JTS).