New answers tagged administrative-boundaries
The country boundaries including the territorial waters are available in the OSM data set. I found a site wher these country shapes can be downloaded https://osm.wno-edv-service.de/boundaries/
After a fixed time for searching I would use the GADM database, copy&paste the levels and territory names to Excel or Access, and try to join both. ADM levels 2 and 3, depending on the country, seem to provide geometry and names to join with.
The AGEB is part of the National Geostatistical Framework (abbreviated as MGN in Spanish) it's not an official administrative level so you're right in that it's not used for administrative purposes but for statistical and census geo-referencing purposes, however, it's so heavily used for research that it would make sense to have the MGN levels mapped to OSM ...
Top 50 recent answers are included