Are there any official maps of Nirn that include Akavir? Or are most just fan artwork?

I also wonder if there is anything in the lore about completely unexplored continents that we have yet to hear a name for? I like the idea of Nirn being a vast place that we have barely scratched the surface of.

Last question! Nirn is often described as a plane and the sun and stars are holes in the sky, so is Nirn actually a spherical planet like earth floating in space, is it even finite?