The third reason for using the presented location-
View concept concerns performance. When the display
has to be redrawn, the POIs already drawn on
the locationView can be easily queried and reused.
Instead of first clearing the entire screen and afterwards
re-initializing and redrawing already visible
POIs, POIs that shall remain visible, do not have to be
redrawn. Furthermore, POIs located outside the field
of view after a rotation are deleted from it, whereas
POIs that emerge inside the field of view are initialized.
Fig. 2 sketches the basic algorithm used for realizing
this locationView2.