There is a total of 6 maps, Every map has 15 to 20 interest points, they are marked as triangles facing down if you open the map pressing
When you also open the map, if you look at the top right corner, it'll tell you how many interest points you have discovered for the specific map.
This might or might not come naturally if you play the game for very very long and like to go loot interest points for better supplies.
Quickest way to do this, get into a game without equipping any guns or supplies and Run! Keep marking your next undiscovered interest point with
as you're running around and get to them. It might require you more than one match on the same map, and sometime you play the same map twice.
Important note : if you try to select matchmaking in selected maps, it'll never find a game, I mean you can be in a waiting lobby as long as many many minutes and still nothing. Just click random match and wait for the right maps to pop up, some of them are more frequent than others but the game is pretty good at shuffling them up a little.