Bug report #12730

"Check Geometry Validity" produces incorrect result

Added by Daniel Baston about 5 years ago. Updated about 5 years ago.

Status:Closed
Priority:High
Assignee:-
Category:-
Affected QGIS version:2.8.1 Regression?:No
Operating System: Easy fix?:No
Pull Request or Patch supplied:No Resolution:
Crashes QGIS or corrupts data:No Copied to github as #:20830

Description

The following is a valid, two-part MULTIPOLYGON:

MULTIPOLYGON (((-71.757875 44.565735, -71.748526 44.560716, -71.758014 44.564355, -71.757875 44.565735)),
((-71.760777 44.567292, -71.75725 44.56739, -71.757875 44.565735, -71.760777 44.567292)))

The "Check Geometry Validity" tool reports the following:

1,segment 0 of ring 0 of polygon 0 intersects segment 0 of ring 1 of polygon 1 at -71.757875, 44.565735
1,Geometry has 1 errors.

Using build 2863f20

Associated revisions

Revision 3eef29ab
Added by Jürgen Fischer about 5 years ago

geometry validator: fix touching lines check (followup b9b9bc3, fixes #12730)

Revision 2a066d89
Added by Jürgen Fischer about 5 years ago

geometry validator: fix touching lines check (followup b9b9bc3, fixes #12730)

(cherry picked from commit 3eef29ab1bd4cc007b7db5012dad23d9c39e2249)

History

#1 Updated by Arnaud Morvan about 5 years ago

The two parts of the polygon have one point in common.
In Settings/Options/Digitizing/Feature creation, there is two options for validity checking which are QGIS or GEOS.
When checking the validity from ftools menu entry,
QGIS method effectively returns that the poligon is not valid:
1,segment 0 of ring 0 of polygon 0 intersects segment 0 of ring 1 of polygon 1 at -71.757875, 44.565735
1,Geometry has 1 errors.
GEOS method returns that the polygon is valid.

#2 Updated by Giovanni Manghi about 5 years ago

  • Status changed from Open to Feedback
  • Category set to 44

Arnaud Morvan wrote:

GEOS method returns that the polygon is valid.

shoud we close this then?

#3 Updated by Daniel Baston about 5 years ago

That's interesting. Is the intent of the "QGIS Method" to validate against a different set of rules than GEOS / OGC?

#4 Updated by Daniel Baston about 5 years ago

  • Assignee set to Jürgen Fischer

#5 Updated by Jürgen Fischer about 5 years ago

  • Category deleted (44)
  • Assignee deleted (Jürgen Fischer)

#6 Updated by Jürgen Fischer about 5 years ago

  • Status changed from Feedback to Closed

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