Image Number 12 for United States Patent #6212474.
A route guidance program and method are disclosed. Maneuver data structures are formed that include data from a geographic database for each location along a route at which a maneuvering instruction is to be provided. These maneuver data structures are used to form a list of tokens. A token can be either a character string or a symbol that refers to another item of data, which can be either a character string, audio data, or graphics data. Maneuvering instructions are provided by explicating the tokens in the list of tokens. Explicating the tokens is done by providing all the data contained in or referred to by the tokens in the order specified in the list of tokens. If the token is a character string, explication includes providing the character string data contained in the token. If the token is a symbol, explication includes providing the data referred to by the symbol, which can be either a character string, audio data, or graphics data. The list of tokens is built by combining sequences of tokens. A sequence of tokens is formed for each of the maneuver data structures. Each sequence of tokens is formed from a output list formed by application of a rules set to the data in the respective maneuver data structure. The contents of an output list for a maneuver data structure can include symbols and keys. Symbols in an output list are used to form tokens which are included in the sequence of tokens formed for that maneuver data structure. Keys in an output list refer to data in the corresponding maneuver data structure. Keys expanded to form tokens which are included in the sequence of tokens formed for that maneuver data structure.