This app mainly works on big cities like NY, SF, LA, London, Paris, Amsterdam, Berlin, etc. The concept is to give an "at a glance" information of where pokemons are and how close they are to despawn. Hope you enjoy !
Why wouldn't it work outside of bigger cities?
@stinhambo turns out the API only work in these, I don't really know why. Maybe to cache pokemons more efficiently for more people.