Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It only takes a minute to sign up.
Sign up to join this community
I was trying to correct the country shapefile of Uzbekistan for Gas flares:
Input layer (the UZB_adm1) differenced by this layer.
In QGIS the result was that the overlapping regions - where the differencing should have taken place - were gone. I presumed it was due to wrong referencing of the UZB shapefile. Couldn't resolve it somehow. After several desperate hours I went to gvSIG 2.2, did the differencing job there. And it worked like a charme. Has anyone an Idea what was wrong in QGIS?
If you run a tool where the results are not what you expected, a good test is to use the Check Geometry Validity from Vector > Geometry Tools > Check Geometry Validity. I ran this for your Gas Flares shapefile and it returned a couple of intersection errors:
To resolve this, you can use v.clean from the Processing Toolbox, select the cleaning tool snap and set the Threshold to 0.01:
In the Advanced parameters tab, you only need the Cleaned output so you can ignore the Errors one.
Now you should be able to use the Difference tool on your "UZB_adm1" layer with the "Cleaned" layer:
