Being manner of loading the map data which loads portion of the map data

摘要

PROBLEM TO BE SOLVED: To efficiently cut out map data required for navigation from a CD, a DVD, etc. in which overall map data is recorded to a work area for map data storage provided to the inside of a memory in the system.;SOLUTION: Map data are constituted as a collection of section map data for each section area acquired by divisions into rectangles along longitude and latitude lines. Sections, through which a reference line connecting a starting point to a destination in a straight line passes, are specified with reference to map data held in an external medium. Section map data of the specified sections is read from the external medium. Then sections, including at least part of a square area having the reference line as a diagonal line, are specified. Section map data of the sections specified, until the work area is filled sequentially from sections having a shorter vertical line drawn from the center of the specified section to the reference line, is read.;COPYRIGHT: (C)2006,JPO&NCIPI