|
Home Theory Images Download |
Theory |
First Cartogram ImplementationThe HistoScale-Approach by Daniel Keim, Michael Panse et al. is already in theory a most promising algorithm for generating cartograms in real-time. ConceptThe basic idea of the HistoScale method is to distort the map regions along the two euclidian dimensions x and y. The distortion depends on two parameters, the number of data items which are geographically located in this map area, and the area covered by this map region on the underlying familiar land-covering map.The distortion operations can be efficiently performed by computing a histogram with a given number of bins in two euclidian dimensions x and y to determine the distribution of the geo-spatial data items in these dimensions. The two histograms are independent from each other, that means, the computation of the histograms can be random. The two consecutive operations in the two euclidian dimensions x and y realize a grid placed on a familiar land-covering map. The number of histogram bins can be given by the user. For a practicable visualization we suggest 256 histogram bins for both histograms. (HistoScale - D. Keim, M. Panse, et al.) Implementation-IssuesStraight forward implementation process. The basic concept is clear and each implementation step is comprehensible. First results can be obtained very quick.Pro's and Con's+ Straight forwared implementation.+ Algorithm with good performance. (real-time) - Pseudo-Cartogram results. (approximation) - Rectangular basis of algorithm visibile. |