In QGIS, at SQL query intersection results in a geometrycollection column with points, linestrings and multilinestring. (first image)

I only need linestrings and multilinestring geometry to calculate the lenghts.

Using ST_CollectionìExtract I tried to select only linestring geometries but I obtain linestring empty for point geometry. (second image).

Extract collection

Query intersection

  • If there are no sub-geometries of the right type, an EMPTY geometry will be returned. So if you want to obtain Lines, you will get empty geometry for the points. What result do you expect to get? – Moh Jun 29 '18 at 11:06
  • A result without point. Maybe I could try to add a condizione 'WHERE ST_lenght (geom) > 0'. – Daniele Piccolo Jun 29 '18 at 13:42

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