I don't know if there's anything more illustrative of the ASOIAF fandom than this thread. In it, people go wild trying to figure out what some symbols on maps in TWOIAF mean. Suggestions go from COTF, Valyria, secret caves, and more https://old.reddit.com/r/asoiaf/comments/id5b2c/spoilers_extended_this_still_hasnt_been_solved/

loads of tinfoil and people pitching ideas about what these things are supposed to be. Being TWOIAF, I asked Elio and Linda about what these things are and they said https://twitter.com/westerosorg/status/1296469570325225475

Looked up the artist in the back of the book, Michael Gellatly, and just shot him an email asking what these things are.

He wrote back this:

Sometimes, a lot of times, not everything is a hint or a secret symbol of meaning. As George answers when he gets hit with tinfoil, sometimes a cigar is a just a cigar. And that's what happened here. They're just decorations Mr. Gellatly added for realism to his maps.

They tell you the prevailing winds and weather conditions in that region. That's it. Because you go nuts trying to decode symbols like they are the secrets to the meaning of ASOIAF, take a deep breath. You're not living in the movie National Treasure.

This answer got massively downvoted, and it's actually correct. https://old.reddit.com/r/asoiaf/comments/id5b2c/spoilers_extended_this_still_hasnt_been_solved/g26yh22/

Reading through the thread, 1 user guessed almost exactly correctly among the tinfoil party. Well done, thedwarfthatrides https://old.reddit.com/r/asoiaf/comments/id5b2c/spoilers_extended_this_still_hasnt_been_solved/g2758cq/