Hello,
in some countries admin_level=4 are on the coastline. This in my opinion would be the the right way to mark a subnational border.
In Somalia and Yemen (countries where I’m working on) admin_level=4 are on maritime borders, as the national borders.
As I’m checking the relations and add the int_name, could I change this without harming nobody’s vision?
Not Somalia and Yemen, but most countries, like Oman, UAE, Iran, Egypt, Turkey, Libia, Finland, Sweden, Norway, Russia, India, Thailand, Malysia, Indonesia, China, korea, Japan …
That section in wiki pages is related to
CIT: “In the United States of America, NOAA nautical charts specify in Note X:”
So, there’s not a worldwide rule, but we should follow the single countries rules. I’m italian and I know here the maritime borders are applied just to the national borders.
I will try to investigate in the UN geoportal, but as the subnational borders are usually not a political matters, I don’t know if I can find an answer there.
[EDIT: checking against the UN geoportal, all the administrative borders are cut to the coastline. So I can’t get any information whether a country apply maritime boundaries to the admin_level 4/6 or not]
So, I think the definitive answer is asking to the local communities