After our experiences with users of the system, we introduced an arrow system to help guide users to portals. Our aim is to avoid doubt in the user’s mind as to whether they are “doing it right” without destroying the enjoyment of a treasure hunt style game. So the arrows point the user in the correct direction without giving away the exact location. There are different colours of arrows depending on whether the user is close enough for activation. The figure below shows the ones which appear when close.

Extract from user guide document describing arrow system