[gdal-dev] Re: what does "Ring Self-intersection at or near point" really mean ?

[Jukka Rahkonen]

Anders Moe <anders.moe <at> geocap.no> writes:

> 
> 
> Hi again.
> 
> I was pointed to the OpenJUMP -> Tools -> QA -> Validate Selected layer
in order to perform a QA test on the file in question , namely "fields" 
from (Oil Fields in the North Sea)
> 
> http://www.npd.no/engelsk/cwi/pbl/en/factmap/download/
  shapes_welcome.htm
> 
> 
> OpenJUMP reported no errors, but GDAL reports warnings. What has me 
worried is what impact this might have on the various OGRGeometry 
geometry comparison routines.

And when I repeated the test I did find two self-intersections with
OpenJUMP and both cases were real data errors. Thus more tests are 
needed before we can judge that gdal is reporting about non-existing 
topology errors.

-Jukka Rahkonen-