A device selectively loads map tiles into its memory while re-using others. As a user chooses different sections of a master map to be displayed, the device determines an intersection between the formerly and currently viewed sections. The device copies selected references to map tiles in the intersection, with some re-indexing, from an array for the formerly displayed section into an array for the newly displayed section. The view of the map might be a three-dimensional perspective view of a two-dimensional surface. The device can create bounding boxes around polygonal perimeters of the viewed areas. The bounding boxes are divided into rectangles corresponding to the tiles located on the master map. The device determines which rectangles within the bounding boxes both (a) contain portions of their respective polygons and (b) overlap each other respective to their locations on the master map. The device already stores map tiles for those rectangles.