Amnoon Oasis Cartographer "?"

What is that area above Amnoon Oasis? I can't access it, but on a map I am looking at for Cartogrpaher, they have gotten in there. map

It is the spherecal area with an x in the center with what looks like a bit of the sea to the left of it.

Anyone know how to get in there?

It is a random arena map.

It's an old PvP arena that was abandoned when A-Net moved all the PvP stuff to the Battle Islands. You don't need to uncover it to max Cartographer title.

ah ok. Thanks. Good to know.