Map reference locating foil - is inserted in map book and pivoted until scale values correspond to reference

摘要

The location of a map reference on a street plan or map produced in book form is facilitated by a hinged foil with numerical scale markings. The reference finder is manufactured as a sheet of transparent rigid plastic that has a hook-shaped hinge to locate in the fold of the book. The triangular shaped foil has a projection for alignment with a page in the folded condition. Three numerical scales are marked on the foil. For a map reference given as 44-28-10 the location is identified as being on page 44. The foil is moved until one scale corresponds with the top edge of the map and corresponds to a value of 28. The final location is provided by point 10 along the foil diagonal scale.