https://issues.qgis.org/https://issues.qgis.org/favicon.ico2016-03-19T12:25:45ZQGIS Issue TrackingQGIS Application - Bug report #14532: Dissolve and Spatial Query doesn't workhttps://issues.qgis.org/issues/14532?journal_id=690342016-03-19T12:25:45ZAnita Graseranitagraser@gmx.at
<ul></ul><p>Please attach the files you mentioned.</p> QGIS Application - Bug report #14532: Dissolve and Spatial Query doesn't workhttps://issues.qgis.org/issues/14532?journal_id=690352016-03-19T12:46:35ZFederico Gianoligianoli.federico@gmail.com
<ul><li><strong>File</strong> <a href="/attachments/download/9737/problems.rar">problems.rar</a> added</li></ul><p>I'm sorry, here the files.</p>
<p>Thanks</p>
<p>Federico</p> QGIS Application - Bug report #14532: Dissolve and Spatial Query doesn't workhttps://issues.qgis.org/issues/14532?journal_id=690442016-03-20T01:08:57ZAnita Graseranitagraser@gmx.at
<ul></ul><p>The dissolved layer has tons of problems, while the original layer is completely fine. That's what most likely throws off the spatial query tool. Did you use dissolve from the vector menu (ftools) or from Processing?</p>
<p><img src="https://issues.qgis.org/attachments/download/9739/dissolve_errors.png" alt="" /></p> QGIS Application - Bug report #14532: Dissolve and Spatial Query doesn't workhttps://issues.qgis.org/issues/14532?journal_id=690452016-03-20T01:09:20ZAnita Graseranitagraser@gmx.at
<ul><li><strong>File</strong> <a href="/attachments/download/9739/dissolve_errors.png">dissolve_errors.png</a> added</li></ul> QGIS Application - Bug report #14532: Dissolve and Spatial Query doesn't workhttps://issues.qgis.org/issues/14532?journal_id=690462016-03-20T01:29:45ZAnita Graseranitagraser@gmx.at
<ul><li><strong>Category</strong> set to <i>Processing/QGIS</i></li></ul><p>I now tried three dissolve algorithms in the Processing toolbox:</p>
<ul>
<li>QGIS Dissolve: The result didn't even contain all input features</li>
<li>SAGE Dissolve: Looked ok but Spatial Query didn't select any centroids as "within" </li>
<li><strong>GRASS Dissolve: This worked!</strong> Spatial Query selected 590 out of 591 as "within" (one is slightly outside of the polygons)</li>
</ul> QGIS Application - Bug report #14532: Dissolve and Spatial Query doesn't workhttps://issues.qgis.org/issues/14532?journal_id=690502016-03-20T07:45:08ZFederico Gianoligianoli.federico@gmail.com
<ul></ul><p>Thanks Anita,</p>
<p>I used Dissolve from processing toolbox.<br />so, in order to have a right multipart polygon, I have to use the GRASS tool?</p>
<p>In your opinion, why the dissolve tool doesn't work correctly?</p>
<p>Thanks a lot for your test.</p>
<p>Federico</p> QGIS Application - Bug report #14532: Dissolve and Spatial Query doesn't workhttps://issues.qgis.org/issues/14532?journal_id=690532016-03-20T10:05:42ZMaximilian Krambach
<ul></ul><p>As to why QGIS Dissolve leaves out output: GEOS:combine (which is used by QGIS:dissolve) returns eight geometry errors, and in the output eight polygons are missing. I guess that QGIS:dissolve only writes "correct" geometries as output. Those "defect" geometries are cases where an inner ring touches the outer ring.</p> QGIS Application - Bug report #14532: Dissolve and Spatial Query doesn't workhttps://issues.qgis.org/issues/14532?journal_id=690542016-03-20T10:21:31ZAnita Graseranitagraser@gmx.at
<ul></ul><p>I guess the main issue with QGIS:dissolve's behavior is that there are zero warnings in the tool log or the QGIS message log. Instead, it just silently drops the features ...</p> QGIS Application - Bug report #14532: Dissolve and Spatial Query doesn't workhttps://issues.qgis.org/issues/14532?journal_id=690552016-03-20T10:27:51ZMaximilian Krambach
<ul></ul><p>If I edit out the validity checks in <a href="https://github.com/qgis/QGIS/blob/99e21a7e5bd45a8612640a1c2ff0133a972e86ba/python/plugins/processing/algs/qgis/Dissolve.py" class="external">dissolve.py</a> , the polygon is dissolved just fine. Maybe dissolve should check for validity on the input, not the output</p> QGIS Application - Bug report #14532: Dissolve and Spatial Query doesn't workhttps://issues.qgis.org/issues/14532?journal_id=690882016-03-23T06:52:41ZMaximilian Krambach
<ul><li><strong>Status</strong> changed from <i>Open</i> to <i>Closed</i></li></ul><p>QGIS Dissolve fixed in master (<a class="changeset" href="https://issues.qgis.org/projects/qgis/repository/revisions/bec849c4f5dee1908f37ca49eb00ae831e99d64c" title="Merge pull request #2935 from matakuka/dissolve changed check for validity from isGeosValid() to...">bec849c</a>). Includes warnings to processing log, works with spatial query and does not drop valid geometries.</p>