||Number||beyond this distance the tiles and layers are thrown away. This parameter is optional. If it is not set it is set to 3.|
All layers which are more than maxAllowedDistance steps away are completely discarded with tiles and map layer.
Checks what border tiles should be discarded after a move. While the user is only moving the map and not zooming it the number of border around the visible tiles are highered and tiles of the maptypes and other zoom levels are discarded.