Method of making update information of map data and...

Data processing: vehicles – navigation – and relative location – Navigation – Employing position determining equipment

Reexamination Certificate

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C701S210000, C701S211000, C340S995190, C707S793000

Reexamination Certificate

active

06453233

ABSTRACT:

CROSS REFERENCE TO RELATED APPLICATION
This application is based upon Japanese Patent Application No. Hei. 11-245414 filed on Aug. 31, 1999, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to methods of making update information of map data, and particular to a method of making update information of map data for updating map data stored in an electric device such as a terminal unit or a map display apparatus to up-to-date information by a unit of picture data. Here, the electric device is for fetching map data from a storage medium such as CD-ROM or DVD-ROM in which the map data is stored in advance and for displaying the map data. This invention also relates to differential data of map data updating systems.
2. Related Art
Hereinafter, a vehicular navigation apparatus will be used for explaining background of this kind of electric devices.
Conventionally, a vehicular navigation apparatus fetches map data which is necessary to realize each function including a map display or a route calculation from a storage medium (such as CD-ROM, DVD-ROM) in which map data has already stored.
Incidentally, the map data in the CD or DVD (hereinafter, described as “CD/DVD”) provided to the vehicular navigation apparatus becomes out-of-date when new roads are constructed, when shapes of roads or traffic regulations are changed, or when several facilities are newly constructed or closed.
Therefore, the CD/DVD is sold with periodically (e.g., annually) updating the map data therein. The procedure will be explained in detail. At first, original data of the map data (hereinafter, called “original map data”) to be stored in the CD/DVD is periodically updated (newly made). Thus, up-to-date original map data is made. After that, CD/DVD of up-to-date version is made by editing the up-to-date original map data. The up-to-date CD/DVD is sold. Here, the making of the CD/DVD by editing the original map data means that the original map data is edited, and then the edited map data is written into a blank CD or a blank DVD.
According to the conventional vehicular navigation apparatus, the user needs to purchase the CD/DVD every time the new version CD/DVD is issued, when the user desires to keep up with up-to-date information.
Here, a system of updating map data (differential update system) has been proposed in JP A 9-145383 or JP A 9-90869. According to this system, differential information (in detail, added, deleted, or changed data) between old map data in the CD/DVD, stored in the vehicular navigation apparatus and up-to-date map data, is transmitted from the external base center to the vehicular navigation apparatus by using radio communication or the like. The vehicular navigation apparatus updates the old map data to the up-to-date map data based on the differential information from the external base center.
When this kind of differential update system is actualized, the user of the vehicular navigation apparatus can obtain road information based on the up-to-date information without purchasing the up-to-date CD/DVD every time it is issued.
Incidentally, the differential information to be provided to the navigation is update information for partially updating the old map data to the up-to-date map data. Therefore, when this kind of differential update system is actualized, the differential information needs to contain information that which data in the map data is updated or how is the data updated.
In this case, the navigation apparatus needs to search particular data to be updated, corresponding data contained in the differential information having sent from the center, in the CD/DVD. After that, the navigation apparatus updates the searched data based on particular information which indicates update contents contained in the differential information.
However, in the case of such a system, when the data to be updated is graphic data which indicates a shape of graphic such as a polygon or a line (so-called “link”), the following inconvenience will occur.
The graphic data contained in the map data in the CD/DVD of the navigation apparatus is formed as shape point coordinate train data which is a coordinate train on an outline of the graphic. Therefore, the navigation apparatus needs to search the data that having the same graphic data sent from the center by graphically comparing each other one by one in the CD/DVD. As a result, it would take a long time to complete the update compared to the update of the other data such as names or address of the roads or facilities.
Furthermore, in general, when the original map data is edited to make the CD/DVD, data reducing process (editing) such as a shape-deform process or a thin out of the shape point coordinate train data to reduce the amount of data. Therefore, even if the graphic data stored in the CD/DVD and the graphic data contained in the original map data illustrate the same contents, each of the shape point coordinate train (each coordinate itself or the number thereof) has slight difference.
Therefore, for example, when several data are prepared in the center at the following timings (1)-(3), the navigation apparatus (at a side of user who purchases the CD/DVD) may cause the following inconvenience.
At a side of the external base center, it is assumed that the following processes are performed.
TIMING (1): At first particular original map data A and a CD/DVD (A) made by editing the particular original map data A are prepared.
TIMING (2): After that, a shape-change of the park a existing in the original map data A is performed. Then, an original data B is generated from the original map data A. A CD/DVD (B) made by editing the particular original map data B is prepared. Differential information a′ regarding the shape-change of the park a is prepared.
TIMING (3): A shape-change of the park a which has been changed in the TIMING (2) and existing in the original map data B is performed again. Then, an original data C is generated from the original map data B. A CD/DVD (C) made by editing the particular original map data C is prepared. Differential information a″ regarding the shape-change of the park a changed in the TIMING (2) is prepared.
Moreover, in this case, it is assumed that a user X has purchased the CD/DVD (A), a user Y has purchased the CD/DVD (A), and a user Z has purchased the CD/DVD (B).
Here, it is assumed that only the user X receives the differential information a′ at the timing (2), so that the navigation apparatus of the user X updates the data of the CD/DVD (A). (The user Y does not receive the differential information a′ at the timing (2). The user Z does not need to receive the differential data a′.)
In such a situation, when all of the users X, Y, Z receive the differential information a″ at the timing (3) to update the data in their CD/DVD, the users Y and Z can update the data in the CD/DVD without any trouble. However, in this case, the user x may not be able to update the data.
This is because the graphic data illustrating the park a in the CD/DVD (A) becomes different from that in the CD/DVD (B) as a result of updating at a point when the CD/DVD of the user X updates the data based on the differential information a′. In this case, when the navigation apparatus tries to search the graphic data corresponding to the received differential information a″, the navigation apparatus may detect that there is no corresponding graphic data.
This kind of inconvenience may cause due to the editing of the CD/DVD at the external base center (the shape-deform process or the thin out of the shape point coordinate train data) or due to an internal process of the update process in the navigation apparatus (regeneration of the graphic data).
SUMMARY OF THE INVENTION
This invention has been conceived in view of the background thus far described and its object is to precisely update map data stored in a storage medium to up-to-date contents.
According to the present invention, new original map data including gra

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