[geos-devel] [GEOS] #1034: Union topology exceptions lead to complete loss of floating point precision

[GEOS]

#1034: Union topology exceptions lead to complete loss of floating point precision
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 Reporter:  dannytoone   |       Owner:  geos-devel@…
     Type:  defect       |      Status:  new
 Priority:  major        |   Milestone:  3.9.0
Component:  Default      |     Version:  3.8.0
 Severity:  Significant  |  Resolution:
 Keywords:               |
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Comment (by dannytoone):

 Just gave it a runthrough on my dataset, and with the exception of a stack
 overflow error (fixed by increasing the stack size through `-Xss`), it ran
 flawlessly. I fully expected to see a bunch of exceptions, but it handled
 them all really well. Visually I can't find any flaws in the result.

 The operation was basically a process to flatten a bunch of geometries
 using a process similar to this: http://blog.cleverelephant.ca/2019/07
 /postgis-overlays.html

 My full dataset is probably too big to post here, but here I'll try to
 attach a photo of the resulting geometries to get an idea at what I was
 throwing at it.

 Not sure if it would be useful to find a way to get you this dataset for
 exploring the behavior around topology exceptions that are handled
 internally. I know for a fact that this same dataset will reproduce the
 error linked above in the postgis tracker.

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Ticket URL: <https://trac.osgeo.org/geos/ticket/1034#comment:4>
GEOS <http://trac.osgeo.org/geos>
GEOS (Geometry Engine - Open Source) is a C++ port of the Java Topology Suite (JTS).