[Qgis-developer] LINEARRING not valid

[Casper Børgesen (CABO)]

Hi all

I have a simple LINEARRING which I would like to use for processing:

LINEARRING (592457.52 6227645.26,592454.37 6227645.98,592448.43 6227647.35,592454.15 6227672.3,592428.66 6227678.14,592422.51 6227651.33,592412.78 6227653.56,592419.05 6227680.86,592424.64 6227691.08,592465.86 6227681.63,592457.52 6227645.26)

When I insert it into QGIS 2.18.2 using the QuickWKT plugin and afterwards run the "Vector\Geometry Tools\Check validity" (method: QGIS, GEOS reports it as valid) on the resulting layer, I get an error saying:

    segments 0 and 9 of line 0 intersect at 592457.52, 6227645.26

The LINEARRING comes from a valid polygon and I would expect the LINEARRING to require some form of intersection at that point, since it's the start and end point of the ring.

I have tried doing a "Vector\Geoprocessing tools\Fixed distance buffer" with zero distance on the layer, but it returns a "None" geometry.

Why is this ring invalid? Is this due to numeric precision and what can I do to circumvent it?

Regards, Casper
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-developer/attachments/20170111/f6b3f192/attachment.html>