Fundamentals of Wearable Computers and Augmented Reality, 2nd Edition

421Use of Mobile Augmented Reality forCultural Heritage

During initialization, the system also registers as an observer for orientation

changes. As a result, the system receives the notications that are generated when a

user changes location or moves the device to look in another direction. The applica-

tion uses this information to redraw the marker icons and update the distance labels

shown on the map and in the list.

Both CroMAR and the original tour guide prototype showed all POIs in the

direction the user was looking. However, this became a problem when the number

of POIs increased and the marker icons started to overlap. In this situation, the users

would have to use the timeline to lter the POIs, not because they were interested in ...