  This paper discusses the implementation of the pervasive game PacMap.
Openness and portability have been the main design objectives for PacMap. We
elaborate on programming techniques which may be applicable to a broad range of
location-based games that involve the movement of virtual characters over map
interfaces. In particular, we present techniques to execute shortest path
algorithms on spatial environments bypassing the restrictions imposed by
commercial mapping services. Last, we present ways to improve the movement and
enhance the intelligence of virtual characters taking into consideration the
actions and position of players in location-based games.
