Generalisation and Multiple Representation

Multi-scale maps

6604.3 - Variable-scale maps in real-time generalisation using a quadtree data structure and space deforming algorithms

Thursday, July 6
3:30 PM - 3:50 PM
Location: Virginia B

Variable-scale maps have been advocated by several authors in the context of mobile cartography. In the literature on real-time map generalisation, however, corresponding methods that resolve cartographic conflicts by deformation of the underlying map space together with the map foreground, are underrepresented. This paper demonstrates how the concept of a malleable space can be applied as a part of the generalisation process and incorporated into the overall methodology of point generalisation. Two different algorithms are used, a density-equalising cartogram algorithm and Laplacian smoothing. Both methods work in real-time and are data-driven. In addition, they allow for a parameterisation in combination with a quadtree data structure, as well as a combination with ‘classic’ generalisation operators (e.g. selection, aggregation, displacement) based on the quadtree. The quadtree serves both as a spatial index for fast retrieval and search of points, and as a density estimator to inform generalisation operators. The use of the quadtree as a common spatial index provides a tool to combine variable-scale maps with classic generalisation. A combination of the two allows, at small map scales, the maintenance of detail in dense areas and data reduction in sparse areas. Additionally, it facilitates building a modular workflow for real-time map generalisation.

Pia Bereuter

postdoctoral fellow
Department of Geography, University of Zurich

Pia Bereuter is a postdoctoral researcher at the URPP ‘Dynamics of Healthy Aging’ and the Department of Geography at the University of Zurich

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Robert Weibel

Professor
Department of Geography, University of Zurich

Professor of Geographic Information Science at the Department of Geography at the University of Zurich, GIS Center. Chair of ICA Commission on Map Generalization and Multiple Representation, 1991-2003. Regional Editor for Europe and Africa, International Journal for Geographical Information Science. Principal investigator or co-investigator of about 50 projects since 1992. Current research interests: Digital cartography and map generalization; computational movement analysis; spatial analysis in linguistics.

Presentation(s):

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Pia Bereuter

postdoctoral fellow
Department of Geography, University of Zurich

Pia Bereuter is a postdoctoral researcher at the URPP ‘Dynamics of Healthy Aging’ and the Department of Geography at the University of Zurich

Presentation(s):

Send Email for Pia Bereuter


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