Research on the methods of connecting contour lines' breakpoints

摘要

As is well known, the contour line has always been the key unit in such projects of automatic recognition of geographic maps, but how to handle the contour lines' breakpoints automatically is still not settled thoroughly. This paper first synthetically analyzes four classical algorithms of the contour lines' breakpoints connecting methods, then presents a layering-based breakpoints connecting policy. Taking brown plate map as data source, separately recognizing and extracting the influencing factors such as elevation annotation, dry riverbeds, cliffs symbols which lead to the contour lines' long-distance break from the map as the reference layers, then judging on the reference layer when connecting the breakpoints, and according to the different influencing factors, designing the corresponding algorithms to achieve the true connecting of the contour lines.