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.
What would be the correct way?