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I have thousands of polygons (buffers) in a single layer and I have a points layer containing tree species. The tree species points shapefile has an attribute called Tree_Type. I need to select only the polygons that contain/intersect three particular species (as shown below). I've already tried multiple intersects to no avail. enter image description here

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Using the new virtual layer with the SQL script in the form window add 2 layers and run the SQL script:

SELECT DISTINCT (a.geometry) geom FROM buffer a JOIN tree_pts b ON ST_Intersects(a.geometry, b.geometry) WHERE b.tree_type='pear' OR b.tree_type='apple' OR b.tree_type='orange'

Save the result as a new file using <Export>-<Save objects as... >

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  • I'm trying this in PostGIS now as QGIS was crashing. I've tried using AND to get each buffer that contains all tree_types but it doesn't work? I've also tried the above code with WHERE Tree_Type.Feature_Ty IN ('Apple', 'Pear', 'Orange') but this doesn't work either. Any thoughts?
    – Dunuts
    Dec 13, 2020 at 9:19
  • I can assume that your polygon file has the wrong geometry...
    – Cyril Mikhalchenko
    Dec 13, 2020 at 9:47
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You can use first the processing tools "join attributes by location" and next "Dissolve" to remove duplicates. Yours polygons need to have a unique id attribute. enter image description here enter image description here enter image description here enter image description here enter image description here

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