Creates a perimeter around your starting area - giving you an island start without putting you in an ocean world. The perimeter will scale up with the starting area you choose in your map settings, but will not scale below the spawning radius for starting resources.
This mod has been incorporated to IslandStart. If you dig around in the settings, there's a (basically legacy) option to put up a giant wall or moat, and it uses the same code Bastion did.