We present TopoVW, an efficient heuristic for map simplification that deals with a variation of the generalization #R##N##R##N#problem where the idea is to simplify the polylines of a map without changing the topological relationships#R##N##R##N#between these polylines or between the lines and control points. This process is important for maintaining clarity #R##N##R##N#of cartographic data, avoiding situations such as high density of map features, inappropriate intersections.#R##N##R##N#In practice, high density of features may be represented by cities condensed into a small space on the map,#R##N##R##N#inappropriate intersections may produce intersections between roads, rivers, and buildings. TopoVW is a#R##N##R##N#strategy based on the Visvalingam-Whyatt algorithm to create simplified geometries with shapes similar to#R##N##R##N#the original map, preserving topological consistency between features in the output. It uses a point ranking#R##N##R##N#strategy, in which line points are ranked by their effective area, a metric that determines the impact a point#R##N##R##N#will cause to the geometry if removed from the line. Points with inferior effective area are eliminated from the#R##N##R##N#original line. The method was able to process a map with 4 million line points and 10 million control points#R##N##R##N#in less than 2 minutes on a Intel Core 2 Duo processor.
['Mauricio G. Gruppi', 'Salles V. G. Magalhães', 'Marcus V. A. Andrade', 'W. Randolph Franklin', 'Wenli Li']
An Efficient and Topologically Correct Map Generalization Heuristic