Interactive Scale-dependent multidimensional Point Data Selection using enhanced Polarization Transformation

Different fields such as Geovisualization, Web mapping or thematic and topographic cartography all need to incorporate a most recognizable and faithful representation of the real world by different map objects at different scales. The objective of this work was to enhance the existing point selection method - the Polarization Transformation - to an automatic scaledependent point data selection method for multidimensional point data sets, which is implemented in an interactive (Web-) user interface. Benefits of the new method are that in the resulting point selection the global as well as the local characteristics of the spatial point distribution and of the spatial point density are preserved; both for 2D- and 3D- point data sets. Within an interactive user interface the user can upload a point data set, define either the achieved output scale or the wanted number of points to be selected. Then the determined results using the enhanced polarization approach are shown in 2D or 3D to the user. In this work an existing 2D point selection evaluation method for points, based on Voronoi areas, was enhanced for 3D point selection evaluation by using Voronoi volumes. Thus the evaluation verified the similarity of point density and distribution before and after the point data selection.