I've got 8 polygon layers made from buffering point layers. All have index and geometry columns:

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I would like to select areas where at least 3 consecutive buffers intersect (like: buffer_03 & buffer_04 & buffer_05 & buffer_06).

I've got overall over 1 million points so trying to figure an effective way to process this (maybe Python code) as QGIS crashes while trying to Union the layers.

  • I think this should be handled by a Postre/Postgis database ... do u have any sample/sub-sample of your data to share if not confidential ?
    – Snaileater
    Mar 19, 2020 at 8:02
  • Hi, good idea. Unfortunately I can't share the data, but as you can see from the images a simple case with computing problems. I would do union 8 times but it grows rapidly ...
    – cincin21
    Mar 19, 2020 at 9:36
  • are you able to aggregate these 8 layers in a postgis table, keeping an attribute to discriminate them and run an SQL query on this table ? is it time data ?
    – Snaileater
    Mar 19, 2020 at 10:55
  • each layer is separate day, so there would be no problem adding them to postgis
    – cincin21
    Mar 19, 2020 at 10:56


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