The happn Map is a bit like your Timeline in the form of a Map: you can find all the main locations where you have crossed paths with users during the 14 previous days. For example: you may have crossed paths with a user who caught your eye at a concert 3 days before; you can then find this person on the Map, among all the crossings that happened at this particular location.
Therefore, the Map allows you to experience the Timeline in a new way, for you to find users you have crossed paths with more easily.