The White Circles indicate the location of an known landmark, POI ( Point of Interest), Hunting Structures, Lookout Points, Tent, GroundBlinds & House that you discovered/unlocked.After you unlocked the house, the house icon will become white. Per example, when you first go to an outpost, you will see the icon of the house as green. The Green Circles means unidentified or unactivated.It is represented by an 'Book' icon with 'Map' as the title. It can also be seen in the Huntermate.The Map can be seen by looking on the 'Huntermate' while still being able to see and do anything (walk, run or crawl] in-game.In multiplayer, each player is represented by a colored icon. The map will also display hunting pressure and need zones. He can also set a waypoint via a click of the left mouse button. The player can fast travel to any visited and discovered outpost by clicking on its icon on the map. They can also be marked by visiting lookout points. Exploring the world and discovering points of interest will mark them on the map. The map displays the reserve and how much of it the player has explored at any given point in time.
