Unlocked Charts:

Anno 1404 map unlock settings: Level 1 unlocks only your starting area, Level 2 unlocks some of the map, and Level 3 unlocks the entire map by default.

Level 1: Only the section each player starts in is unlocked.

Level 2: Some of the map is unlocked to start off.

Level 3: The entire map is unlocked by default.

This setting controls how much of the map is initially visible. The more of the map that is initially visible, the less Achievements matter. On Level 3, Achievements are totally pointless. On Level 3, everyone initially gets their choice of islands to settle on, and which may be preferable to having it be decided by luck. You can also immediately tell what specialists are available.