Multi‐visibility maps of triangulated terrains

Abstract

Abstract Visibility computation on terrain models is an important research topic with many applications in Geographical Information Systems. A multi‐visibility map is the subdivision of the domain of a terrain into regions that, according to different criteria, encodes the visibility with respect to a set of view elements. We present an approach for visualising approximated multi‐visibility maps of a triangulated terrain corresponding to a set of view elements by using graphics hardware. Our method supports heterogeneous sets of view elements containing points, segments, polygonal chains and polygons and works for weak and strong visibility. Moreover, we are also able to efficiently solve approximated point and polygonal region multi‐visibility queries. To illustrate the usefulness of our approach we present results obtained with an implementation of the proposed algorithms. Keywords: TerrainVisibilityVisualizationGraphics‐Hardware Acknowledgements We wish to thank Teresa Paradinas for helping us in the initial stages of the implementation of our algorithms. We also would like to thank anonymous referees for their careful reading and comments which have improved the clarity of the final version of this paper. Support of the Spanish Ministerio de Educación y Ciencia under grant TIN2004‐08065‐C02‐02 is gratefully acknowledged. Marta Fort and Narciís Madern are also grateful to the Spanish Ministerio de Educación y Ciencia for funding their respective PhD grants AP2003‐4305 and BES2005‐9541.