Using Shape Analyses for Placement of Polygon Labels
Track: Application Development
Author(s): Hoseok Kang, Shoreh Elhami, Alan Saalfeld
Polygons may be convex or nonconvex, and they may or may not have holes. Label placement algorithms that locate a label at a centroid have only been successful for convex polygons without holes. The automatic labeling function in ArcView does not work well for nonconvex polygons or for polygons with holes. The objective of our proposed method is to provide a better label placement strategy to guarantee that labels are placed in meaningful locations inside all polygons, convex or otherwise, with or without holes. The algorithm we develop uses shape analyses such as compactness, weighted areas, region decompositions, and region skeletons, and it is implemented in Avenue. Our implementation has been used in Ohio for Delaware County's Current Agriculture Use Valuation (CAUV). In this large-scale mapping application, labels were placed on areas representing different combinations of soils and land cover within each parcel participating in the program.
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