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I successfully downloaded the OSM data from https://www.geofabrik.de/ and converted the .osm.pbf file to a .gpkg using og2ogr. Now I want to extract administrative boundaries using DB-Manager and SQL:

SELECT *
FROM multipolygons
WHERE admin_level = 4

However, I need the physical borders, which do not fall in a line with the administrative borders in coastal areas (see picture). Having a look at OSM, for example via QGIS, the information is there, but I can not figure out which key to use and how to extract them.

enter image description here

What would be the correct way?

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  • 2
    Please provide example data for the seaside area, and for the land area.
    – Erik
    Apr 23 at 9:46
  • 1
    Well, that's the problem. I downloaded the russia-latest.osm.pbf from download.geofabrik.de/russia.html and I want to extract the land area separated by the admin borders. If I know the key for the land area I would clip it by myself. But I can not find a way to extract only the land area. Does this make sense?
    – parallax
    Apr 23 at 9:52
  • 2
    Use the shorelines to clip the administrative polygons.
    – Babel
    May 7 at 10:38
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I think you are wrong with the admin_level which should be admin_level=2 instead of admin_level=4, check the OSM's Wiki.

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  • Thank you. I've already spent a lot of time looking for the right query and I know this page. Though, for Russia 'admin_level' starts at 3. However, I need the land area - the physical border of the land area (white polygons of the countries).
    – parallax
    Apr 27 at 11:18

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