A Smoothing Algorithm for Contour Lines by Means of Triangulation
Authors: Irigoyen, Jesus1; Martin, Maria T.2; Rodriguez, Jaime2
Source: Cartographic Journal, The, Volume 46, Number 3, August 2009 , pp. 262-267(6)
Publisher: Maney Publishing
Abstract:
Contour lines are very important features in the representation of quantitative relief over a wide range of scales. As scale is reduced, contour lines should be generalized. One of the generalization routines involves smoothing lineal features. Nevertheless, contour lines are a special class of lineal feature, as they represent a three-dimensional object. Accordingly the generalization should be conducted while taking into account all the contour lines over the map, bearing in mind the three-dimensional object that they represent. The algorithm presented in this paper smoothes the contour line irregularities that generate flat and erroneous triangles in a Delaunay triangulation. Smoothing is achieved by moving only the sharp vertex toward the baricenter of the flat triangle; in an iterative algorithm, this produces a smooth line that does not generate flat triangles.Keywords: ALGORITHMS; GENERALIZATION; DEM/DTM; TRIANGULATION; CARTOGRAPHY; SMOOTHING
Document Type: Research article
DOI: 10.1179/174327709X429401
Affiliations: 1: Departamento de Ingeniería Cartográfica, Geodesia y Fotogrametría, Universidad Politéctica de Valencia, E-46022 Valencia, Spain 2: University of Santiago de Compostela, E-27002, Spain

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