| 摘要 |
A client/server navigation system utilizes partial route guidance trees, enabling a thin, mobile client to detect route deviation and provide alternate instructions while awaiting response from a server. The system (10) consists of a server (28) containing a network database and route-calculation program; a client (26) capable of obtaining (12) its current location and destination, displaying route instructions (22), and determining when it needs additional instructions from the server (20,24); and communication (30,32,34,36) between the client (26) and server (28). The invention allows for long routes and responsive operation on a small, low-powered client despite lags and lapses in communication.
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