| 摘要 |
<p>A sub-station (3-1) extracts graphic data from an optical disk (19), designates a search area F and transmits the data as retrieved data (61) to a base station (1). After the base station (1) has received the retrieved data (61), it extracts graphic data (10) including a search area (69) from a data base (7), and checks the date and time of the update of the graphic data (10) and those of the retrieved data (61). When the update date and time of the retrieved data (61) are older, the graphic data (10) are transmitted to the sub-station (3-1).</p> |
