Are there more?
Drum Island I would guess as the French Alps, from some names like Dalton and Wapol. Definitely seems European with the castle style.
Skypiea thematically always reminded me of you know where between Asia and Africa, but it could be somewhere like the Americas. I've seen a theory it's based on some space thing.
Water 7 I imagine is Venice, although Galley La sounds pretty French.
Jaya I'd guess the Malay Archipelago or the Carribean.
I guess Impel Down has inspiration from Alcatraz?
I imagine most places aren't that strongly based on anywhere though.