| 摘要 |
PROBLEM TO BE SOLVED: To provide a map, on which the present position is simply and accurately read from the longitude and the latitude displayed in a digital form, while carrying a GPS(global positioning system) device and to provide a navigation system which utilizes the map and the GPS device. SOLUTION: The map 6 is a waterproofed GPS reading map and has a scale of one-50,000th. On the map, longitude and latitude lines 1 and 2 are written for every ten seconds. Among these lines 1 and 2, only one minute lines are made into distinguished reference lines. If one carries a portable GPS device 5, which digitally displays the longitude and the latitude of a present position by GPS satellites 7, and the map 6, the navigation system reads the present position with the precision better than an actual error of approximately 20 meter square employing the references of the lines 1 and 2 written on the map 6. |
