Browsing by Author "O'Connor, Mark J."

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    Evaluation of TIN extraction methods for various terrain textures
    O'Connor, Mark J. (Virginia Tech, 1996)
    This study focuses on the Triangulated Irregular Network (TIN) model for representing terrain. A TIN is a vector representation of terrain composed of vertices, lines, and triangular polygons. The elevation values are stored in the vertices. TINs are used in Geographic Information Systems (GIS) for terrain analyses. In particular 1 compare TIN extraction methods. A TIN extraction method is a method in which points are selected from a raster Digital Elevation Model (DEM) in order to construct a TIN. Evaluations of TIN extraction methods have been performed in the past. However, none have compared the TIN extraction methods with terrain texture. This study compared and analyzed the four most popular TIN extraction methods: VIP, Hierarchy, Drop Heuristic, and LATTICETIN. Comparison of the TIN extraction methods was based on the 90th percentile of the absolute error, the absolute error being the absolute difference between TIN elevation and DEM elevation at each point. The results indicated that LATTICETIN yielded the lowest 90th percentile errors for all types of terrain textures and Drop Heuristic was second best in most instances. The Hierarchy method was superior to VIP when less than 12% of the original DEM points were selected. When 12% of the original DEM points were selected, VIP outperformed the Hierarchy method. A correlation was found among TIN accuracy and terrain texture. There was a direct relationship between the two variables.