Vigor

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.

The season two update has made this a little easier. Each map has up to 20 points of interest, listed in the top right of the map. When looking at the map while loading or by pressing up on the d pad once in the encounter, you will notice the POIs labeled with triangles. If the triangle is completely filled black, you have already discovered it. It it is unfilled, with some white, then you have not discovered it.

Just work your way around the map, each time you discover a new location a notification will display at the top of the screen. Once you have discovered them all, whether in a single encounter or many, the achievement will pop without the need to extract.

As for tips, I only have a few:
The triangles do not show elevation, so if you are right one without discovering it, look up for a bridge or upper floor, or down for a cave or tunnel entrance.

If it appears to be one structure at the triangle, you may need to enter the structure to discover it. If it appears to be a cluster of structures, then you probably need to be in the middle of the cluster to discover it.

Green symbols, such as the barred house, can cover the triangles. Either check them out or wait until the next encounter on the map.