Hi JF,
Regarding GEOS, please consider asking for more details through the
project's vibrant forum (subscribe at
https://lists.osgeo.org/mailman/listinfo/geos-devel ), I know there was
a big release made yesterday and some chatter (project home:
https://libgeos.org/ ) GEOS is one of those core libraries, who would
greatly appreciate your direct feedback.
PS. hello from the east coast
Thanks,
-jeff
--
Jeff McKenna
GatewayGeo: Developers of MS4W, MapServer Consulting and Training
co-founder of FOSS4G
http://gatewaygeo.com/
On 2022-06-03 4:25 p.m., Bourdon, Jean-François (DIF) via QGIS-Developer
wrote:
Intranet logo
Hi Devs,
I had a surprising issue with a specific vector layer and a clip
operation. Validity check of the geometries seem to be done differently
if native:clip is used inside a processing script or manually through
the GUI as a vector layer containing a linestring with duplicate node
like LINESTRING ((0 0, 1 0, 1 0)) won't cause an issue when the clip is
done with the GUI but will halt if done inside a processing script (on
QGIS 3.22.6).
Also, if I run */qgis:checkvalidity/* with the *GEOS* method, no error
is found, but if I run it with the *QGIS* method, it finds one error
(/line 1 contains 2 duplicate nodes starting at vertex 2/). So here are
my questions: what exactly is checked when using the GEOS method and
what is checked using the QGIS method? Also, do all processing tools
(qgis: and native: ones) use the same kind of check?
I didn't find anywhere the details of what would be considered an error
according to the "QGIS spec". Is it documented somewhere or do I need to
look for hints inside the source code? As for the GEOS method, I only
found some error examples in the PostGIS documentation and in a FME page
(https://community.safe.com/s/article/invalid-ogc-geometry-examples
<https://community.safe.com/s/article/invalid-ogc-geometry-examples>).
Is there an official documentation of what geometries are invalid
regarding GEOS?
Thanks a lot for any pointer
*Jean-François Bourdon, ing.f.*
*Analyste en télédétection*
*Direction des inventaires forestiers*
*Ministère des Forêts, de la Faune et des Parcs*
5700, 4^e Avenue Ouest, local A-108
Québec (Québec) G1H 6R1
Téléphone : 418 627-8669, poste 704304
*_jean-francois.bour...@mffp.gouv.qc.ca_*
*mffp.gouv.qc.ca* <http://www.mffp.gouv.qc.ca/accueil.jsp>
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