A Robust Strategy for Handling Linear Features in Topologically Consistent Polyline Simplification

Polyline simplification is a technique that reduces the number of vertices of a polygonal chain for the purpose of map generalization and for speeding up processing and visualization in GIS. Unfortunately, the majority of simplification algorithms does not preserve the topological consistency of the map, namely the spatial placement of a polyline with respect to itself and to its neighbouring features. To overcome this problem, some approaches based on the consistency of a point feature have been proposed. For the sake of simplicity, they unify the handling of linear and point features by considering a linear feature as a sequence of point features. This solution, however, fails in a few particular cases. In this paper, we firstly examine the reason for it to fail and then present a robust strategy for remedying the remaining problems without abandoning the basic principle of reducing a linear feature to a sequence of point features.