I am trying to merge many layers to one and the only working method I found is by copying features from one layer and paste in the desired layer. I tried to use MMQGIS - Merge tool but I get some geometry error (for e.g. polygon 2.5 ! = Unknown WKB 3003).

I tried with another plugin called multiplelayerselection but something strange happened: you can select all features from visible layers but it will only copy current layer.

What can I do to speed up the process? I have about 10000 layers, so doing one by one is very slow.

  • 1
    You can try to use the plugin Merge Shapefiles if it are Shapefiles. But the problem will probably be the same. The toolos will not work with different geometry types. And it seems that you have different ones.
    – Matte
    Commented Jul 3, 2017 at 13:11
  • Is there a way to change geometries of several layers? I mean they are all polygons but some have "include z-dimension" some have not. Thank you! Commented Jul 3, 2017 at 13:17
  • Not with the standard tools. With some Python knowledge you can merge them based on the geometry or change the geometry. But you would need some basic programming skills.
    – Matte
    Commented Jul 3, 2017 at 14:59
  • So, there is no way with an addon or something like that? I dont have any programming skills Commented Jul 4, 2017 at 5:46
  • You might be able to automate your process using the processing modeler. qgis.org/en/site/forusers/visualchangelog200/…
    – csk
    Commented Jul 4, 2017 at 17:31

1 Answer 1


You can use the MMQGIS plugin to convert your geometry type from polygon Z (2.5D) to polygon (2D): MMQGIS->Modify->Convert Geometry Type. Then to merge multiple layers try Vector->Data Management Tools->Merge vector layers. Select all layers you want to merge, specify location and name for output file then click run. I have never tried to merge as many layers as you have, though, so I am not sure how well this method will work or how long it would take.

  • I tried this method but I see that you can only change geometry of current layer and that takes time. I'm now using copy and paste, one by one. Commented Jul 4, 2017 at 7:29

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