If you play alone, the place where the map doesn't open doesn't exist yet. World generation happens when you visit a new area. The parts of the world that fall within your view radius are generated. This is why the save file gets so big when you travel a lot. More draw distance = more generation = more map opens (but the game can lag and your hard drive space quickly decreases). For playing with friends (I'm not sure) there was an addon for sharing maps.
We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.
AnniPicto's post in is there a command or mod or anything like that that would reveal the world map for me? was marked as the answer