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<p>I'm seeing very strange behaviour with a particular shapefile in
QGIS 3.4.1. The data can be obtained here:</p>
<p><a class="moz-txt-link-freetext" href="https://drive.google.com/file/d/1BPVnsUbJREYh6TvLM07GAzXMiMneHemN/view?usp=sharing">https://drive.google.com/file/d/1BPVnsUbJREYh6TvLM07GAzXMiMneHemN/view?usp=sharing</a></p>
<p> When I run the <i>Vector Geometry > Dissolve</i> Processing
tool on it, no errors are raised, an output layer is created
containing one row with no geometry. This happens regardless of
the Processing 'Invalid features filtering' setting.<br>
<br>
Running the <i>GDAL > Vector geoprocessing > Dissolve</i>
tool on the data immediately returns an invalid geometry (self
intersection) error, but running <i>Vector Geometry > Check
validity</i> finds no errors using either the GEOS or QGIS
engine.<br>
<br>
If the <i>Vector Geometry > Dissolve</i> tool is run on a
selection from the shapefile, it will complete successfully if all
but one feature is selected, <b>regardless of which feature is
left unselected</b>.</p>
<p>I'm not sure whether this is a bug, or my data. Does anyone have
any explanation for the observed behaviour?</p>
<p>Cheers,</p>
<p>Andy<br>
</p>
<pre class="moz-signature" cols="72">--
Andy Harfoot
GeoData Institute
University of Southampton
Southampton
SO17 1BJ
Tel: +44 (0)23 8059 2719
<a class="moz-txt-link-abbreviated" href="http://www.geodata.soton.ac.uk">www.geodata.soton.ac.uk</a>
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