I have this polygon layer, which contains dissolved buffers that were originally created around separate points. I want to extract the points (which lie at the center of each circle) from the layer. So I need to undo the dissolving of the buffers and then find the point which lies at the centre of each circle. How do I do this in QGIS?

This is what the polygon layer currently looks like:

enter image description here


1 Answer 1


Try buffering with a negative distance, then find the centroids.


  1. Points along geometry to create ~two points on the border of each buffer circle

  2. Geometry by expression to create lines at each point location perpendicular to the circle segment. See Perpendicular lines on line using QGIS extend(make_line($geometry, project ($geometry, 40, radians("angle"-90)) ), 600, 0 ) Adjust the lengths.

  3. Line intersections to get one or multiple points at each intersection.

enter image description here

You can of course create the point layer manually using snapping and place two points per circle.

  • 1
    Thank you! It worked by using step 1 & 2 and then manually making the point layer with snapping!
    – Roos
    Jun 23 at 12:19

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