1. A method for implementation in a computing device for generating map images, the method comprising: receiving, via a communications network, a plurality of base map tiles associated with a first map image for a selected geographic region, each base map tile including one or more vector descriptors that indicates a geometry of a respective map element in accordance with a vector graphics format; preprocessing, using a processor, the vector descriptors in each base map tile to create a first set of rendering instructions for rendering the first map image as defined by the plurality of base map tiles; receiving, via the communication network, a set of difference map tiles for rendering a second map image for the selected geographic region, each of the set of difference map tiles including one or more indications of a modification of a vector descriptor to be applied to one of the plurality of base map tiles; preprocessing, using a processor, the one or more indications of the modifications of the vector descriptors to create a second set of rendering instructions for rendering the second map image; rendering, using a processor, the second map image by implementing the first set of rendering instructions and the second set of rendering instructions; and displaying the rendered second map image via a user interface.