Method and apparatus of route guidance

摘要

Systems and methods of route guidance on a user device are provided. In one aspect, a system and method transmit partitions of map data to a client device. Each map partition may contain road geometries, road names, road network topology, or any other information needed to provide turn-by-turn navigation or driving directions within the partition. Each map partition may be encoded with enough data to allow them to be stitched together to form a larger map. Map partitions may be fetched along each route to be used in the event of a network outage or other loss of network connectivity. For example, if a user deviates from the original route and a network outage occurs, the map data may be assembled and a routing algorithm may be applied to the map data in order to direct the user back to the original route.

主权项

1. A method of generating a route to a destination comprising:
prefetching, with a processor of a user device, a first plurality of map partition data for a first area from a remote computer at a first point in time, each of the first plurality of map partition data being encoded with information for generating driving directions; determining, at a second point in time later than the first point in time, whether the remote computer is accessible;if the remote computer is accessible, fetching, with the processor, a second plurality of map partition data for a second area from the remote computer at the second point in time, the second plurality of map partition data being encoded with information for generating driving directions, the second area being within a predetermined distance from a current location of the user device and partially intersecting the first area;
storing the first plurality of map partition data and the second plurality of map partition data in a memory; determining, at a third point in time later than the second point in time, whether the remote computer is accessible; if it is determined that the remote computer is not accessible, assembling map data representing a geographic region, the map data being an assemblage of at least one of the first plurality of map partition data and the second plurality of map partition data stored in the memory; and generating a route to a destination using the map data.