1. A method for converting source image data to tile data comprises the steps of: (a) selecting at least one source image set; (b) computing a scaling value for the at least one source image set; (c) selecting a base scale for a tile set to be created based on the scaling value; (d) establishing the tile set geographic bounds of the tile set; (e) converting the tile set geographic bounds to discrete tile bounds; (f) for each source image from each of the at least one source image sets (i) determining source image geographic bounds of the source image; (ii) if there is an intersection between the source image geographic bounds and the tile set geographic bounds; (1) loading the source image from a LRU cache, if possible; (2) if the source image is not in the LRU cache, loading the source image into the LRU cache; (3) extracting image data from the source image at the intersection; (4) scaling the image data based on the base scale; (5) storing the scaled image data to a tile storage mechanism; (g) clearing the LRU cache; and (h) repeating steps (a) through (g) for each of the at least one source image sets.