It's a realm whose focus is that of chaos. To catalog it, map it, or anything, is an impossibility. Even with the airship that Yuma Tsukumo has, specific coordinates need to be placed, and it's usually only because those places are anchored. To wander it otherwise is akin to suicide, unless you are a part of that realm.

*... she rubs her arm a bit* It... Doesn't help that my world... *she trails off herself* ... There's no real entry point now, that wouldn't be inherently dangerous to just enter.