<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 14 (filtered medium)"><style><!--
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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span lang=DE><o:p> </o:p></span></p><p class=MsoNormal><span lang=DE><o:p> </o:p></span></p><p class=MsoNormal><span lang=DE>Hi,<o:p></o:p></span></p><p class=MsoNormal><span lang=DE><o:p> </o:p></span></p><p class=MsoNormal>I have a Multiline layer A with about 900 Features loaded (only a few of those are actually multi part geometries) in QGIS 2.14 and I try to do Vector -> Geoprocessing Tools -> Difference with Layer A as the input vector layer and Layer A as the difference layer, expecting to get as a result an empty layer. But, the Output Shapefile has ~150 Features in it. Topology Checker says, there are no invalid geometries, but there are about 90 pseudo nodes in the layer. I started snooping around and found other line shapes that behave this way. Have I fundamentally misunderstood what a difference is, or is there some specific geometry problem that causes difference to behave oddly? The use case is silly, but I started with comparing an exported shape to its source, got weird results, and then tried to compare the source to itself as a sanity check. Now I feel I might have lost sanity. Help?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Heather<o:p></o:p></p></div></body></html>