Here is a link to a map of all encounters......please note that these
ARE exact locations
BUT when they show up is a little random........
http://images.akamai.steamusercontent.com/ugc/47092047626562...What I did was downloaded the map, right-clicked it, and clicked "EDIT", so it would open in PAINT....That way, I could "circle" the ones I knew for sure I got, as I got them....
Please note: I used this map to get most of them on my easy playthrough but accidentally deleted my save before I could finish and had to start over on Normal so I can get NG+.......that is the only reason I don't have this cheevo yet....I used this same map when I got this cheevo on the 360 version......
Hope this helps!