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I have two shapefiles with polygons: one is regions for a country and the other is the protected areas inside that country.

I have merged these two polygons with Union, but the regions and protected areas are currently overlapping. I would like the area where they overlap to be only the protected areas (when merging, I would like to assign a higher ranking to protected areas). However, I don't want the entire region underlying the protected area to be deleted, JUST where they overlap, so one new map is created with protected areas and regions without gaps. they do not have any attributes in common so I'm not sure how to do this in QGIS.

What it looks like (protected area in grey overlapping green regions):

enter image description here

What I want (one layer with merged protected areas and no overlap with regions):

enter image description here

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  • Sorry, your question is unclear to me: you have one or two polygon layers? And you finally want regions and protected areas on separate layers? You want to "cut out" the shape of protected area form the regions? If so, have a look at Menu Vector / Geoprocessing Tools / Difference.
    – Babel
    Commented Jan 21, 2021 at 20:15
  • By the way, your screenshots do not help much to understand: which polygons are protected areas, which one regions? Also the difference between the two images is not evident to me. Could you please improve the question and screenshots?
    – Babel
    Commented Jan 21, 2021 at 20:15
  • Apologies. I have two layers.shapefiles with multiple polygons (one with regions and one with protected areas). I want to merge these 2 shapefiles to create one new one; one layer, with the regions and protected areas together but where the overlapping polygons are deleted and only the protected area polygon remains.
    – Nat
    Commented Jan 21, 2021 at 21:50
  • OK, than use, as proposed, Menu Vector / Geoprocessing Tools / Difference. Hope that solves your problem?
    – Babel
    Commented Jan 21, 2021 at 21:52
  • Lovely I did this and then used union on the difference output and protected area layers and seemed to work thank you!
    – Nat
    Commented Jan 21, 2021 at 22:05

1 Answer 1

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First, run "Difference" from the Processing Toolbox and choose your Regions as Input and your Protected Areas as Overlay:

enter image description here

This difference layer will now have some holes:

enter image description here

Now run "Merge Vector Layers" from the Processing Toolbox and choose your Protected Areas as well as the Difference-Layer as Inputs:

enter image description here

Alternatively, you can use the "Union"-Tool:

enter image description here

Run it, and done:

enter image description here

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  • This is so straightforward thank you!
    – Nat
    Commented Jan 25, 2021 at 12:36

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