I’m not sure to be in the correct subtopic for my question but I didn’t found better.
I try to use Overpass API over Europe OSM data. I want to get all European country (+ their islands). Example, for France : Metropole + Corsica + Guadeloupe + Martinique…
To do it, I downloaded europe OSM datafile from geofabrik : https://download.geofabrik.de/europe-latest.osm.bz2 because I saw that in Europe folder I can get all what I wanted. Example : Europe/France/Corsica+Guadeloupe+Martinique… and same things for others countries.
My initial goal was : to get European countries (geographic) + all islands associated to them (example : France is an European country, so I want also their islands : in Europe like Corsica + outside Europe like Martinique, Guadeloupe…).
So please explain which data you mean when you write “I want to get all European country (+ their islands)” It might be obvious to you what you need, but it is not for the people that want to help you.
That is correct. The file you downloaded from geofabrik doesn’t contain any objects outside the polygon shown on http://download.geofabrik.de/europe.html. That is why you can’t find any data for the overseas islands. You will have to download more OSM data somehow.
The Europe extract intentionally does not include any data on the overseas parts of European countries, which are not inside the polygon.
Typically, you’d merge them together before loading into a database. “osmium” is one way of doing that, “osmosis” is another. One thing that a map server that I run does is splits a downloaded file into several pieces, translates each piece into a different language, and merges them all back together. The script that does all this (using osmosis) is here: https://github.com/SomeoneElseOSM/SomeoneElse-style/blob/master/update_render.sh .
There’s also documentation on osmosis and osmium in the OSM wiki and linked from it.