I have several polygons (all of which have the same CRS and attributes) and I want to merge these into a single layer. I had hoped this would be a quick, easy process in QGIS but the merge functions (listed under data management tools and the one that is part of MMQIS) fails and instead report that the layers must be of the same geometry.

I am aware that Grass may provide a solution to this issue - as per Error in merging 2 shape files of different geometry types - but my knowledge of QGIS is limited and I would rather focus on that than needing to get my head around GRASS as well. Is there a simple function in QGIS that can resolve this issue?

  • 2
    Did you try the processing plugin (installed by default) and its "merge vector layers" algorithm? Oct 21, 2016 at 12:42
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    Some layers are probably MultiPolygon layers. You can try using the Multipart to single parts tool and run the merge tool again.
    – Joseph
    Oct 21, 2016 at 12:44
  • Thanks Joseph, Matthias for coming back to me so quickly with two good suggestions. I'm using QGIS ver 2.16 and the "merge vector layers" algorithm which forms part of the processing plugin appears to be exactly the same as the merge function listed under data management tools Kuhn 1 hour ago Jos
    – Rich28
    Oct 21, 2016 at 13:58

1 Answer 1


Having selected 'save vector layer as..' I stumbled upon the fact that one of the shapefiles I was attempting to merge included the 'z-dimension' as part of its geometry, whilst the other files didn't feature this. I re-saved all the shapefiles I need to merge, specifying in each case that the geometry type was 'polygon' and that the 'z-dimension' was unchecked, then re-ran the merge process - on this occasion successfully

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