Information terminal device and method of generating map data

An information terminal device comprising:

• a map database unit to store therein map data having a feature information data list in which pieces of feature information each representing a feature are arranged, an attribute information data list in which pieces of attribute information each of said feature are arranged, and a relation information data list in which pieces of relation information each including attribute holding type information indicating whether or not there is said attribute information corresponding to said feature information are arranged corresponding to the order of said feature information;
• a navigation function execution unit to execute a navigation function;
• and
• a data access unit to acquire map data to be used by said navigation function execution unit from said map database unit and associate said feature information with corresponding attribute information in the order of arrangement of said relation information when said map data to be used by said navigation function execution unit is acquired from said map database unit,
• wherein an arrangement of said attribute information data list is made corresponding to the order of said feature information and when said attribute information corresponding to said feature information arranged in said feature information data list does not exist, said arrangement of said attribute information data list is made with said attribute information omitted, and
• said relation information associates said feature information with said attribute information when said attribute holding type information indicates that there is said attribute information corresponding to said feature information.

A method of generating map data comprising:

• generating a feature information data list in which pieces of feature information each representing a feature are arranged;
• generating an attribute information data list in which pieces of attribute information each of said feature are arranged;
• and
• generating a relation information data list in which pieces of relation information each including attribute holding type information indicating whether or not there is said attribute information corresponding to said feature information are arranged corresponding to the order of said feature information.

An information terminal device comprising:

• a map database to store therein map data having a feature information data list in which pieces of feature information each representing a feature are arranged, an attribute information data list in which pieces of attribute information each of said feature are arranged, and a relation information data list in which pieces of relation information each including attribute holding type information indicating whether or not there is said attribute information corresponding to said feature information are arranged corresponding to the order of said feature information;
• a processor to execute a program;
• and
• a memory to store the program which results in performance of steps comprising,
• executing a navigation function;
• acquiring map data to be used in executing said navigation function from said map database;
• and
• associating said feature information with corresponding attribute information in the order of arrangement of said relation information when said map data to be used in executing said navigation function is acquired from said map database,
• wherein an arrangement of said attribute information data list is made corresponding to the order of said feature information and when said attribute information corresponding to said feature information arranged in said feature information data list does not exist, said arrangement of said attribute information data list is made with said attribute information omitted, and
• said relation information associates said feature information with said attribute information when said attribute holding type information indicates that there is said attribute information corresponding to said feature information.