We present a study of people’s use of positional information as part
of a collaborative location-based game. The game exploits self-reported positioning
in which mobile players manually reveal their positions to remote players
by manipulating electronic maps. Analysis of players’ movements, position
reports and communications, drawing on video data, system logs and player
feedback, highlights some of the ways in which humans generate, communicate
and interpret position reports. It appears that remote participants are largely untroubled
by the relatively high positional error associated with self reports. Our
analysis suggests that this may because mobile players declare themselves to be
in plausible locations such as at common landmarks, ahead of themselves on
their current trajectory (stating their intent) or behind themselves (confirming
previously visited locations). These observations raise new requirements for the
future development of automated positioning systems and also suggest that selfreported
positioning may be a useful fallback when automated systems are unavailable
or too unreliable
