The representations of the map are provided on the surface of a rotation body (4). The two lateral edges of the map locate at both sides of a narrow dividing strip (5) which runs on the surface of the rotation body from top to bottom. At the upper and lower ends of the rotation body a cap section (7) free from the representations is provided. The rotation body is a ball and the dimensions of the representations reduce continually from the equator (6) of the ball formed by a large circle to the poles. The ratio of the dimension at a specific point on the ball surface to the dimension on the equator corresponds to the ratio between the periphery of the equator to the periphery of the circle parallel to the equator on which the specific point is located.
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