US Patent 8223172 Regional map zoom tables

A graphics or image rendering system builds application-oriented tables on a server that are downloaded to a client device responsive to a request for map data from the client device in association with a mapping application at the client device. The table or tables specify by geographic region which zoom levels have map data different from other zoom levels and may apply to many types of map data including map vector data, map label data, satellite image data, traffic data, transit status, etc. The table or tables allow the mapping application to skip zoom levels for which no new data is available, or conversely, reuse data from other levels when rendering a level not requiring new data from the server.