The detail is marvelous, the images are suggestive of how a map might be contrived from the image ... and best of all, there is a real sense of how one journeys from one plane to the next. The astral conduits set my mind going, where as the transition between Prime Material and the Ethereal planes is coincidentally something I've had in mind for years, reaching back into the early 2000s.
Some of it strongly reconciles with Robert A. Heinlein's Number of the Beast, which is probably one of his more obscure books nowadays but which was in the '80s very well known. Sometimes, being old, I feel like a crusty old bastard who remembers the Indian Wars of the 1870s talking to a bunch of doughboys who have just got back from the trenches in France. It must sound strange for you young 'uns who don't remember anything before 9/11. Anyway, the Number of the Beast posits a dimensional travel that proposes all the many universes fits onto six axes ~ and that the axes compound three dimensionally:
~ the number of the Beast. This, Heinlein posits, enables real access to even fictional universes. Heinlein then takes his characters Deety, Zeb, Jacob and Hilda, with their intelligent air car Gay Deceiver on a journey to places like Oz and Barsoom, as well as eventually meeting the authors Heinlein and Isaac Asimov at a party. As Asimov was alive when the book was written in 1980 and the pair were good friends, I'm sure they had a laugh about it.
The map is of French origin, which is probably why it is done so well. I'd love a more detailed labeled version ~ and might feel compelled to create one, if there was time to run this many games for this many settings.
Have you seen the very, very terrible film, What Dreams may Come? Give me the power to create a universe like Robin Williams' character does in the film and watch the sort of D&D setting I'd create.
Hah. Did I tell you my other name was Ego the Living Planet?
Here's a link to the map above and some description below.