The following map was posted by Lady Nerevar of The Imperial Library on her tumblr. It shows roughly the continents of Nirn scaled to those of Earth. Lots of surprising things in this revelation. The size of Akavir, the existence of Lyg (A realm said to be a parallel version of Tamriel, where Mehrunes Dagon was created as mentioned in Mythic Dawn Commentaries 4) and how big Yokuda once was.
See the tumblr site for further notes. Any trolling/comments about how this isn't "canon" etc. adds nothing to the discussion and will be removed.