| 主权项 |
1. A method comprising:
defining first and second levels of a navigation database, the first level divided into a plurality of first tiles, and the second level divided into a plurality of second tiles, the second tiles being larger than the first tiles; storing a plurality of link data records in the first level of the navigational database, the plurality of link data records representative of a plurality of road segments in a geographic region; determining, by a processor, one or more link data records of the plurality of link data records to be stored in the second level, the determining based on a position of each of the plurality of link data records relative to the plurality of second tiles; storing, based on the determining, the one or more link data records in the second level; determining a starting link set including at least one link data record of the plurality of link data records that crosses a tile border of one of the plurality of second tiles of the second level and has a travel direction that extends into the tile border; determining a destination link set including at least one link data record of the plurality of link data records that crosses a tile border of one of the plurality of second tiles of the second level and has a travel direction that extends out of the tile border; and calculating an optimal route, based on a cost function, between each of the at least one link data records in the starting link set and the at least one link data records in the destination link set, each optimal route including one or more link data records stored in the first level of the navigation database, wherein storing the one or more link data records in the second level comprises storing the one or more link data records that are part of each optimal route in the second level of the navigation database, wherein the optimal route is operable to be presented on a display. |
