| 摘要 |
PROBLEM TO BE SOLVED: To easily use position information from application by reducing the complexity of processing in the case that an overhead for the retrieval of a place name where a user exists and also application manages the position of the user. SOLUTION: The names and coordinates of users are acquired from position detection means 10 to 12 and the place name of each user is obtained from the coordinates of the user. On the other hand, a tree structure data store means 16 stores the place name of the user at a node and the user name resident in the place name as leaf data. When the user moves, the place name of the user is acquired from the coordinates of a moving destination, then, the user name of a moving origin is deleted out of the tree structure data and the user name is entered in the leaf data at the node of the place name of the moving destination. For retrieving the position of the user, the node is retrieved from the user name and route information from the root to the node of the tree structure is outputted. For acquiring the name list of the user present at the relevant place from the place names, the node corresponding to the given place name is retrieved and the user name stored as the leaf is outputted to the node. |
