[Qgis-user] Difference between QGIS and GEOS method ?

[Jürgen E. Fischer]

Hi Harrissou,

On Thu, 27. Apr 2017 at 13:16:13 +0200, DelazJ wrote:
> This is indeed a question I frequently see and also wonder what the
> differences are. Also because, according to the one you select, checking
> validity tools for example do not return the same results. So I think users
> need to know the difference and make the appropriate choice.
> *(if a qgis dev is in the neighborhood...)*

The QGIS method is an internal method that can return multiple errors and was
IIRC introduced, when GEOS could just report one error at a time without a
location and we couldn't or didn't yet use it threaded.  Essentially it was
just made to highlight digitizing errors.  It might miss some rules or
interpret some edge cases differently than GEOS.


Jürgen

-- 
Jürgen E. Fischer           norBIT GmbH             Tel. +49-4931-918175-31
Dipl.-Inf. (FH)             Rheinstraße 13          Fax. +49-4931-918175-50
Software Engineer           D-26506 Norden             http://www.norbit.de
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