1925	 Concepts of Use in Contour Map Processing	 Generalized techniques whose use can simplify the solution of problems relating to contour maps. One of these techniques makes use of the topological properties of contour maps. The topology is represented by a graphical structure in which adjacent contour lines appear as connected nodes. Another generalized technique consists of utilizing geometrical properties to determine the characteristics of straight lines drawn on the contour map. Both of these techniques have been applied to the problem of locating the ground track of an aircraft from elevation readings obtained during a flight. map contour map contour lines topological properties geometrical properties graph of contour map navigation
