TRANSFER OF MAP DATA OUTSIDE PLOTTING OBJECT IN ACCORDANCE WITH TRANSFER OF THREE-DIMENSIONAL MAP DATA AND ITS DISPLAY SYSTEM

PROBLEM TO BE SOLVED: To create a three-dimensional space by plotting a part of a plotting object and effectively retrieving data of the plotting object from a server and to show the three-dimensional space as if huge three-dimensional map is executed at a client side. SOLUTION: The data transferred from the server (405) is held in a cache memory of a client (406). Only a certain fixed range is three-dimensionally plotted like a flashlight centering around the user (viewpoint) by using cache data and a three-dimensional plotting program (408). Data of background is generated by using the data held in the cache or conventional data (409). In addition, information corresponding to moving history of the user is held while the user is moving (411). Then, the area supposed to be plotted is requested to the server from the information and held in the cache again (412). When a plotting range is transferred in the area by the user, three-dimensional plotting in a fixed range is similary performed.