Authors:
Mauricio G. Gruppi
1
;
Salles V. G. de Magalhães
1
;
Marcus V. A. Andrade
1
;
W. Randolph Franklin
2
and
Wenli Li
2
Affiliations:
1
Universidade Federal de Viçosa, Brazil
;
2
Rensselaer Polytechnic Institute, United States
Keyword(s):
Map Generalization, Computational Geometry, Line Simplification, Geographic Information Systems.
Related
Ontology
Subjects/Areas/Topics:
Artificial Intelligence and Decision Support Systems
;
Enterprise Information Systems
;
Problem Solving
Abstract:
We present TopoVW, an efficient heuristic for map simplification that deals with a variation of the generalization
problem where the idea is to simplify the polylines of a map without changing the topological relationships
between these polylines or between the lines and control points. This process is important for maintaining clarity
of cartographic data, avoiding situations such as high density of map features, inappropriate intersections.
In practice, high density of features may be represented by cities condensed into a small space on the map,
inappropriate intersections may produce intersections between roads, rivers, and buildings. TopoVW is a
strategy based on the Visvalingam-Whyatt algorithm to create simplified geometries with shapes similar to
the original map, preserving topological consistency between features in the output. It uses a point ranking
strategy, in which line points are ranked by their effective area, a metric that determines the impact a point
will cause
to the geometry if removed from the line. Points with inferior effective area are eliminated from the
original line. The method was able to process a map with 4 million line points and 10 million control points
in less than 2 minutes on a Intel Core 2 Duo processor.
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