| 摘要 |
<p>A map is provided for indicating the direction of a fixed point (S), such as a sub-satellite point, from any point (P) within a specified area which is a substantial fraction of the earth's surface. The map projection is such that the actual direction to the fixed point (S) is the same as the direction shown on the map, when the map is aligned with a reference direction such as magnetic north. Optionally, the distance to the fixed point on the map represents the elevation of the satellite. Apparatus for using the map includes a holder (10) for the map and for a magnetic compass (18). A scale (22) which rotates about the fixed point on the map has a marker (32) which is positioned over the user's location on the map. The azimuthal direction of the satellite is indicated by an arrow (28) on the scale, while the elevation of the satellite is read off the scale by means of a pointer (34) located on the fixed point on the map.</p> |
