I work with this polygon and try to find a way to create a new polygon from the empty gap (not distinguish it) in the middle of the polygon.

I succeed to do it with a "difference" tool- but used with another layer on the polygon and then using the difference tool.

I can also digitize the shape of the hole and create a new layer- i seeking an automated way to do it and not doing in manually.

I read

Is it possible to do it with a direct tool in QGIS 2.18.1, without aid of another layer?

enter image description here


I recommend Digitizing Tools plugin.

enter image description here

Once installed, you will find a new toolbar. The eighth from the left of this toolbar, there is an icon called Fill ring with a new feature (interactive).

For you to fill all rings at once;

  1. Switch to Fill all rings in selected polygons with new feature mode by clicking on a small triangle (right-hand-side).
  2. Start editing mode and select polygons you want to work on (you can select all polygons).
  3. Click on the tool icon.
  4. A small dialog box will appear and asks you to give a new attribute value. This value will be given all fillings, so that it helps you to identify these new features in the attribute table. Hit [OK] to close.

You can use the trace tool (on the Snapping Toolbar) and simply trace around the hole in the polygon while creating a new feature in a new layer (or your existing layer).

enter image description here

  • i don't want to digitize by manual- i search for automatic action. – newGIS Jan 15 at 11:27
  • where the trace tool location? – newGIS Jan 15 at 13:31
  • on the Snapping toolbar - look at the one I have ringed in red – Ian Turton Jan 15 at 13:32
  • your image is too small – newGIS Jan 15 at 13:35
  • 1
    it is a tool bar - so no not in plugins. Right click on a grey area and select it – Ian Turton Jan 15 at 15:30

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