I asked a question earlier about how to invert my file "hydropolys.shp" from a vector of ocean and seas to a vector of land and got sent to here, but I am experiencing issues where using the "Difference" tool, it returns an empty map.

So I tried to follow the instructions geoprocessing but this tool keeps giving the "Not Responding" error. Any suggestions on what to do next? Or any other easy way to convert the shapefile? I am using QGIS 2.18. Or is there a way to do this instead in code in PyQGIS?

  • You can additionally check this article QGIS 'Difference' tool return empty layers and as was mentioned by @Joseph, you may apply v.clean. – Taras Mar 6 '19 at 6:33
  • did you make sure your features are of the same coordinate system? – Rob Mar 6 '19 at 10:13
  • In my question I mentioned that I tried the v.clean tool given from that link, but it is not working @Taras – user137875 Mar 6 '19 at 13:53
  • Shouldn't the features be of the same system, since I am just creating a new extent layer from my hydropolys layer and then trying to get the difference? – user137875 Mar 6 '19 at 13:54
  • If you've got the chance to upgrade then this tool is MUCH improved in 3.x – ndawson Mar 7 '19 at 6:57

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