Most of the maps seen in the series were made by Kanazawa in his attempt to chart the post apocalyptic world. He lent his maps to Chito and Yuuri to help them find a refueling station that would aid them on their journey to the top layer. He created several maps during his journey but loses them in episode 3 (chapter 8, volume 1) when the bag containing them falls from an elevator. In chapter ?, volume 5, a friendly AI gives them access to a map.
Maps in the Anime
Appearances in the Anime