Thank you for the jumping off point, fascinating! I discovered Tabula Peutingeriana[1]. Is this what you were referring to or are there other layouts to be found?

1a: https://en.wikipedia.org/wiki/Tabula_Peutingeriana

1b: https://en.wikipedia.org/wiki/Tabula_Peutingeriana#/media/Fi...

Edit: I also noticed that the Tabula Peutingeriana is linked in the header of the site, clearly I should be more observant :-)

Yep, Tabula Peutingeriana is easily the best known example and the tip of my tongue that I failed to mention by name :-)

There are others that I have seen in the British Library collection and some in Rome but I'd be struggling to name them - I had a lot of exposure to experts in History of Maps back in the 1980s|1990s when I was working bridging wet film photogrammetry and digital mapping, sadly my main focus was programming, mathematics, lens geometry, unification of existing maps under WGS84.

All the examples I've seen have that subway diagram look, albeit freehanded, and clearly were all part of a tradition of road maps in that related style.

I would love a videogame that uses something like this for a map of the game world.