Wiki/mapareas
In the game
Usage: /setmaparea <set> <area key or none> (the keys: /mapareas)
Usage: /addmaparea <key> <size in metres, 20-6000> [name] (a square centred where you are; an existing key is moved)
Usage: /deletemaparea <key> (/mapareas lists them)
What it does
Not explained in detail yet.