Abstract: A method to compress a very large original geographic database down to a manageable and economical size while preserving accuracy is herein described. Similarly, a method to quickly retrieve, decompress, and display data is herein described. An original geographic database is prepared for compression by dividing it into discrete regions called bounding boxes. The bounding boxes may be variable sized to improve accuracy and compression. Absolute map coordinate data is compressed by converting it to relative map coordinate data. Map files are named in a descriptive manner to allow determination of map file characteristics merely by inspecting the file name. Relative map coordinate data can be displayed without being converted to absolute map coordinate data. Alternately, relative map coordinate data may be quickly decompressed into absolute coordinate data. Retrieving compressed data is facilitated by forming view windows having adjacent load regions pre-decompressed and ready for user display.

Abstract: The present invention utilizes a combination of local area networks and hard-wired wide area networks which communicate with mobile units wirelessly. An alternate embodiment uses a hard wired communication from a mobile unit to a base computer. The wireless local area network is comprised of a base computer unit connected wirelessly to single or multiple mobile units while also being connected to a hard-wired wide area network (such as the internet). The base unit either stores or routes packet data to a wide area network super router that, in turn, routes packets to the base unit computer where the packet data should ultimately reside. The present invention utilizes integrated software and hardware apparatus to identify, track and report tax-deductible vehicle travel routes including actual mileage, stops and routes driven.