Timeline for Deleting sliver polygons after difference operation in QGIS
Current License: CC BY-SA 4.0
11 events
| when toggle format | what | by | license | comment | |
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| Aug 28, 2021 at 13:31 | history | edited | PolyGeo♦ | CC BY-SA 4.0 |
deleted 20 characters in body; edited title
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| Feb 27, 2017 at 8:03 | vote | accept | nkc | ||
| Feb 26, 2017 at 3:17 | answer | added | user92055 | timeline score: 3 | |
| Feb 25, 2017 at 8:43 | history | tweeted | twitter.com/StackGIS/status/835409951027769344 | ||
| Feb 23, 2017 at 12:45 | comment | added | nkc |
Thanks, I'll try it out :) I'm still learning PostGIS to be honest; would the query be something like SELECT ST_Difference(layer1.geom, layer2.geom) FROM layer1 INNER JOIN layer2?
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| Feb 23, 2017 at 12:39 | comment | added | Joseph | That sure is a lot of polygons for each layer...have you considered importing them to PostGIS and using the ST_Difference tool? This should reduce the processing time significantly :) | |
| Feb 23, 2017 at 12:34 | comment | added | nkc | Hey, thanks for replying! The slivers are irrelevant for the purpose of the analysis, and there's around 600.000 polygons in each layer all told - the difference operation itself takes around two hours. Fun times. "Eliminate sliver polygons" seems to want to merge neighboring polygons, which is not what I want, and "v.clean" had no effect (out of the parameter settings I've tried - I'll do an exhaustive search just in case). There ought to be some easy check for whether the geometry in question is a "full" polygon or not, and then I could just iterate over the polygons with a python script | |
| Feb 23, 2017 at 12:17 | comment | added | Joseph |
Those 'slivers' could actually be legitimate differenced polygons and not artifacts but hard to say without looking at your original polygon layers. If you only have a handful of the solid blue polygons, you can select them manually and then right-click the layer, go to Save As... and check the Save only selected features option. Then save it as a new shapefile. Alternatively, have you tried the Eliminate sliver polygons tool or the v.clean tool with the rmdangle parameter?
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| Feb 23, 2017 at 12:06 | history | edited | PolyGeo♦ | CC BY-SA 3.0 |
edited title
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| Feb 23, 2017 at 12:05 | review | First posts | |||
| Feb 23, 2017 at 12:10 | |||||
| Feb 23, 2017 at 12:01 | history | asked | nkc | CC BY-SA 3.0 |