Postgres/PostGIS Spatial Query for Percentage Overlap (and display results in Excel dynamically!)

[@GIS_user]

Great vid on the use of processing in PostGIS. Is encouraging me to use the software! I'm new to using this interface, but can see the benefits of it. I am looking to complete a 'many to many' distance calculation, from 2 vector layers. So that I am given a distance between they layers. E.g I have a national parks polygon and and a settlements polygon, and want to ascertain the distances between each national park and each settlement. Can this be done in PostGIS?

[@StefanoVerugi]

thanks for the video, very informative yes so much can be done without 'clicking around' calling tools by using SQL spatial functions for those who do not have a PostGIS server installed, the same can be done directly in QGIS using DB Manager (or Virtual Layer I suspect) cheers PS if you use ST_overlaps in WHERE don't you miss the patches that are not across areas but lay just inside one? I used ST_intersects instead, is it correct?

[@GISCoordinated]

Yes Intersects is fine. The real difference is that in overlaps a part of the geometry always overlaps the other geometry meaning it is never totally inside. But intersects would return true if totally contained. So there is a subtle difference. I think I did some db manager examples - will have to go back and remind myself. DB Manager is a great tool but I just wanted to show the functionality with PostGIS which is very straightforward to setup and offers great spatial DB experience. Many things are powered by PostGIS including.... ArcGIS OnLine (!)