But if i remember well, then according to the first tome of the History of middle earth book series, the map of the Arda was something like a ship floating in space. A flat "earth" we could say, where the sun and the moon where 2 masts. And in the centre of it was middle earth(thats why its middle ) and in the "driver's position" were the undying lands.
In the history of middle earth book series there are some maps but they are pretty early conceptions. After the creating of the world and the story of the building of valinor there are almost no maps showing arda, but only middle earth.