PURPOSE: To easily plural optional vision maps by using an aerial photograph and a map by calculating the vision area of a satellite from height data on buildings and contour figure data on building bottom surfaces and optional inputted satellite position and height data. ;CONSTITUTION: For the preparation of a satellite vision map 12, a shadow generated by a building model when a light source position is placed at the apparent position of the satellite is calculated geometrically according to the building model and satellite position data 5 and the shadow is displayed on a road map. This shadow approximates to the nonarrival area of the radio wave from the satellite. A map wherein the nonarrival area of the radio wave from the satellite, building bottom surfaces, and roads are displayed in the same image is the satellite vision map 12 and it can be decided whether the satellite can be viewed or not on all the roads in the map. Consequently, a satellite vision map 12 can be prepared even for a different kind of satellite by using an existent building data base 6 by inputting a position, and further the data in the building data base 13 can be updated even when existent data are used.;COPYRIGHT: (C)1993,JPO&Japio
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