| 摘要 |
<p>A sheet forming at least part of a map or atlas, or a transparent overlay for same, is divided (e.g., by sets of parallel lines) into rectangles which are each designated by a respective single number. Each rectangle is or may be subdivided (e.g., by sets of parallel lines) into smaller rectangles each designated by a single number. Each subdivided rectangle may be further subdivided (e.g., by sets of parallel lines) into smaller rectangles which are each designated by a respective single number. A location on the map may be accurately identified by a combination of only two or three numbers (indicating the largest rectangle and the subdivision thereof or the largest rectangle, a subdivision thereof and a subdivision of the latter), thereby simplifying the map of its index. The invention also prides the sheet(s) as described above together with an index of features on the map or atlas. The invention enables a user to find a location on a map (or overlay) quickly and accurately.</p> |
