Representation of Contours ad Regions for Efficient Computer Search A novel computer-searchable representation for the three basic pictorial features, contour maps, region coverage, and line structures, is described. The representation, which has practical storage requirements, provides a rapid mean of searching large files for data associated with geometric position as well as with attribute value. An application of this representation to handling terrain information illustrates its utility. The algebraic properties of the data structure make it computationally easy to determine whether a point lies within a closed boundary; compute the area contained by a closed boundary; generate the closed boundary representing the union or intersection of two closed boundaries; and determine the neighboring boundaries to a point and the minimum distances between them and the point. CACM February, 1973 Merrill, R. D. contour map representation, region boundary representation, computer-search-able structure, graphic data retrieval, graphic language, two-dimensional patterns, computer graphics, graphic display 3.21 3.23 3.79 6.35 CA730201 JB January 24, 1978 3:30 PM 1630 4 2547 2287 4 2547 2547 4 2547 2547 4 2547 2987 4 2547 3062 4 2547 3165 4 2547 1326 5 2547 1925 5 2547 2547 5 2547 2547 5 2547 2547 5 2547 2987 5 2547 1326 6 2547 1630 6 2547 2125 6 2547 2547 6 2547 2633 6 2547 421 6 2547 524 6 2547