Patent ID: 7945382

Claim:
A navigation apparatus comprising: map data storage means for storing map data; read-write means for writing the map data into a portable storage medium and for reading out the map data from the portable storage medium; capacity detection means for detecting maximum storage capacity of the portable storage medium; central coordinates input means for inputting coordinates of a central geographic point of the map data to be written into the portable storage medium; sectional region setting means for setting a central sectional region with a predetermined range including the central geographic point and an outer sectional region of an additional predetermined range surrounding the central sectional region; extracting-region creating means for sequentially creating map data extracting-regions by repeatedly adding an additional predetermined range to the central sectional region; capacity judgment means for sequentially extracting map data, of each map data extracting-region created by the extracting-region creating means, from the map data storage means and for sequentially judging whether or not the volume of map data of each map data extracting-region is equal to or less than the detected maximum storage capacity; storage region determination means for determining the largest map data extracting-region which does not exceed the detected maximum storage capacity; and reading-writing control means for extracting map data, for the largest map data extracting region determined by the storage region determination means, from the map data storage means and for controlling the read-write means to write the extracted map data into the portable storage medium.