Storage medium for map information for navigation system and system for offering map information for navigation system

A navigation system, comprising:

• (a) a first memory for storing first map information, said first map information including (i) information of a highway network covering the whole of a predetermined area and (ii) map information of only a first limited region more detailed than the information of the highway network, said detailed map information of said first limited region including an ordinary road network, and said predetermined area including said first limited region and being wider than said first limited region;
• (b) a second memory for storing second map information, said second memory being separate from said first memory, said second map information including (i) information of at least a part of said highway network in a second limited region and (ii) map information of only a second limited region more detailed than the information of the highway network, said detailed map information of said second limited region including an ordinary road network, and said predetermined area including said second limited region and being wider than said second limited region;
• (c) said first and second memory being in the form of IC memory chips mounted on a circuit board;
• (d) read means for reading said first and second map information from said first and second memory;
• and
• (e) a microcomputer for computing an optimum, based on said first and second map information read by said read means, an optimum route from a starting point to a destination, said starting point being inside one of said first and second limited regions, and said destination being inside the other of said first and second limited regions.

A system for offering map information for a navigation system, comprising:

• (a) a first memory for storing first map information, said first map information including (i) information of a highway network covering the whole of a predetermined area and (ii) map information of only a first limited region more detailed than the information of the highway network, said detailed map information of said first limited region including an ordinary road network, and said predetermined area including said first limited region and being wider than said first limited region;
• (b) a second memory for storing second map information, said second memory being separate from said first memory, said second map information including (i) information of at least a part of said highway network in a second limited region and (ii) map information of only a second limited region more detailed than the information of the highway network, said detailed map information of said second limited region including an ordinary road network, and said predetermined area including said second limited region and being wider than said second limited region;
• (c) said first and second memory being in the form of IC memory cards;
• (d) read means for reading said first and second map information from said first and second memory, said read means having two slot portions for electrical connection with said first and second memory, respectively;
• and
• (e) a microcomputer for computing, based on said first and second map information read by said read means, an optimum route from a starting point to a destination, said starting point being inside one of said first and second limited regions, and said destination being inside the other of said first and second limited regions.