Vantage points are one of the types of collectibles in the game. Typically found up high and overlooking cool points of interest. Once you find one, you'll have to activate your focus and look in the right direction to trigger it. You'll know it counts when it prompts you to play an unlocked audio log. There are 12 of them total scattered across the world and maps can be purchased to give you decently specific locations of where to find them all. Once you're close, you can activate your focus to find a purple blur for a specific location. See the video below for a complete guide to all 12, though you only need one to unlock this trophy.
Full disclosure, this is not my video or my work and I don't take credit for it.