Abstract: A trajectory display device includes: a display element; a current position detector; a memory for storing the current position successively; and a position determination unit for determining a plurality of certain actual distance trajectory points and a plurality of direction change points based on position data stored in the memory. The certain actual distance trajectory points are arranged at every actual distance defined by a scale of a map. The moving body changes a moving direction at each direction change point. The display element displays the trajectory including the certain actual distance trajectory points and the direction change points, which is overlapped over the map.

Abstract: In a course of updating old map data on a hard disk drive to new map data, a low-priority portion of the old map data that has less importance/necessity is deleted to create a vacant area, and a high-priority portion of the new map data is copied to the vacant area as an update of the map data. Then, the high-priority portion of the old map data is deleted to create another vacant area, and a low-priority portion of the new map data is copied to the vacant area. During the update of the map data, restrictions on the usage of the map data are avoided at all efforts by having the high-priority portion of at least one of the new map data and the old map data maintained on the hard disk drive, while maximizing the utilization of storage resources in a map data management apparatus.

Abstract: A trajectory display device includes: a display element; a current position detector; a memory for storing the current position successively; and a position determination unit for determining a plurality of certain actual distance trajectory points and a plurality of direction change points based on position data stored in the memory. The certain actual distance trajectory points are arranged at every actual distance defined by a scale of a map. The moving body changes a moving direction at each direction change point. The display element displays the trajectory including the certain actual distance trajectory points and the direction change points, which is overlapped over the map.

Abstract: In a course of updating old map data on a hard disk drive to new map data, a low-priority portion of the old map data that has less importance/necessity is deleted to create a vacant area, and a high-priority portion of the new map data is copied to the vacant area as an update of the map data. Then, the high-priority portion of the old map data is deleted to create another vacant area, and a low-priority portion of the new map data is copied to the vacant area. During the update of the map data, restrictions on the usage of the map data are avoided at all efforts by having the high-priority portion of at least one of the new map data and the old map data maintained on the hard disk drive, while maximizing the utilization of storage resources in a map data management apparatus.