TL;DR: Maps are usually used better in comics than in prose, but artists need to be careful not to overly define a thing.
The Walt Kelly “Map of Fairy Tale Land” that was posted yesterday is, for me, fictional cartography of the highest level. It’s what would have driven me to hours of distraction as a young person.
While I didn’t have access to that map, I did spend hours poring over charts of Middle-earth, Arrakis, Athas, and many more. The most powerful thing about those maps is the amount of drama and story implicit in each of them. It’s like reading part one of a trilogy and never reading the rest: the mind trips in mad circles of possibility.
Scott McCloud calls this closure; give a reader disparate parts of a story, and the mind fills in the blanks. In McCloud’s case, he’s talking specifically about two panels of a comic and what happens in the gutter in between. For example, a glint of streetlight on an axe in one panel, and a tortured scream above a cityscape in the next. The pain inflicted from axe to scream is unique to the mind of the individual reader.
This happens in prose as well, the but the space for reader input is less explicit. A man stares down at his lover and then walks away. How are his eyes set? How does he walk? In prose, the reader might not construct the scene until they gather more information. In comics, a reader in encouraged by the blank space to fill in the blanks immediately.