The mini-map is blurry around the edges and doesn't display the whole map.
How do I fix this?
This isn't an error or bug, it's actually known (for historical reasons) as 'fog of war'/.
The reason the mini-map doesn't show everything is because you either haven't gone to those places yet or haven't continued far enough in the storyline. You may want to try out playing online as this will allow you to 'view' parts of the map you can't yet view in single player due to the storyline.
Eventually you'll be able to see the entire map, but you might have to travel to certain parts to be able to see it (The game won't force you to go to these places).