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Experience with the handling of spatial data on a computer led to the identification of a variety of ''awkward " problems, including interpolation, error estimation and dynamic polygon building and editing. Many of the problems encountered could be classified as " 'spatial adjacency " issues. The Voronoi diagram of points and line segments in the Euclidean(More)
We wish to extract the topology from scanned maps. In previous work [15] this was done by extracting a skeleton from the Voronoi diagram, but this required vertex labelling and was only useable for polygon maps. We wished to take the crust algorithm of Amenta, Bern and Eppstein [3] and modify it to extract the skeleton from unlabelled vertices. We find that(More)
We wish to extract the topology from scanned maps. In previous work [GNY96] this was done by extracting a skeleton from the Voronoi diagram, but this required vertex labelling and was only useable for polygon maps. We wished to take the crust algorithm of Amenta, Bern and Eppstein [ABE98] and modify it to extract the skeleton from unlabelled vertices. We(More)
Traditional raster-based map or image manipulation techniques are known frequently to produce different results from vector implementations of the same operation. In addition, rasters require re-sampling and information loss for most resizing and rotation transformations , while vector maps in a GIS require complex and error prone procedures to define(More)
Traditional vector and raster spatial models as used in many computer systems are examined to determine what is meant by the term " neighbour ". The limitations are examined and the Voronoi spatial model is proposed as a consistent alternative to both. It is then asked whether this new computer model of space bears any resemblance to human spatial reasoning(More)
This paper examines the problem of polygon digitizing, and suggests an inversion of the traditional approach for polygons of the environmental type, where each individual polygon, rather than its boundaries, is of primary interest. Many workers in geology, forestry, soil science, etc. have found the tedious specification of boundary arcs and their(More)