Sorry for the late response. It's probably not so relevant now, but the gist of it is that they're ley lines. In the map's canon (at the time it was made) they were impassible walls of magic that wreak havoc on the climate and topography of the surrounding geography.
In the new incarnation of the map's canon, they are simply points of interest; points of no return. Mysteries and anomalies. No two explorers will give the same account of what the areas are like, and no one that have ventured further has ever returned. As such, they're regarded as if they were the end (or edge) of the Earth.
In the new incarnation of the map's canon, they are simply points of interest; points of no return. Mysteries and anomalies. No two explorers will give the same account of what the areas are like, and no one that have ventured further has ever returned. As such, they're regarded as if they were the end (or edge) of the Earth.
My canon follows similar ideas, although leylines can also be tapped into by magic users to release incredible power, as well as means to travel faster. A capable magic user could use the leylines to travel within it and wander through it to another place where the leylines connect to. However, this is considered incredibly dangerous and one using the leylines to travel cannot stay there for too long, otherwise they would be lost within its currents forever.