Geolocation in a mobile application

[Noixe]

Hi,

I have never developed for mobile devices (Android or IOS) and I have
a curiosity. It would be possible to develop a kind of game (RPG) that
takes advantage of the geolocation? Basically I was thinking of a game
where the player physically moving to his city, would have the
opportunity to "meet" monsters to fight or even challenge other
players. I do not know if there is already something similar, but
devices like iPhone or Galaxy would allow such a thing?

Thanks