COMPRESSED NAVIGATION MAP DATA

摘要

A method for generating a compressed navigation map database from uncompressed navigation map data, wherein the uncompressed navigation map data contains different building blocks of navigation data, each building block addressing a functional aspect of the navigation data, each block containing strings of data. The method includes determining, for each block of the uncompressed navigation map data, most frequent substrings of the block; storing, for each block, the determined most frequent substrings of the block in a seed block; replacing, for each block, in the strings the determined most frequent substrings stored in the seed block by a reference to the seed block thereby generating a compressed block for each block; and storing, for each block, the compressed block and the seed block in order to generate the compressed navigation map database.

主权项

1. A method for generating a compressed navigation map database from uncompressed navigation map data, the uncompressed navigation map data containing different building blocks of navigation data, each building block addressing a specific functional aspect of the navigation data, each block containing strings of data, the method comprising the steps of:
determining, for the building blocks of the uncompressed navigation map data, most frequent substrings contained in the building blocks; storing, for the building blocks, the determined most frequent substrings in at least one seed block; replacing, in the building blocks, in the strings the determined most frequent substrings stored in the at least one seed block by a reference to the at least one seed block thereby generating a compressed block for each building block; and storing the compressed blocks and the at least one seed block in order to generate the compressed navigation map database.