Patent ID: 8005612

Claim:
A map distribution system including a map distribution server that distributes map data and a navigation device that receives said map data, said map distribution server comprising: a map update data management table having a plurality of first entries, each first entry including a respective set of map update data in correspondence with a map update data ID for the respective set of map update data and a map update data ID for each other set of map update data upon which the respective set of map update data included in the first entry depends; a memory that stores a per-area map update data management table having a plurality of second entries, each second entry including an area identification of an area of said map data in correspondence with a version of the area and the map update data ID for each set of said map update data that has necessarily been applied for the area identified by the area identification of the second entry in the version of the second entry; a map update data manager that refers to said per-area map update data management table to select the map update data ID for each set of map update data required for updating an area selected based on an input from said navigation device and the required map update data ID for each other set of map update data upon which any set of map update data required for updating the area selected depends; and a communication device that distributes each set of map update data corresponding to each selected map update data ID.