Tolerance for barycentric coordinates in georrefered attribute interpolations

• Autor(a) principal: Barbosa, Ivanildo
• Data de Publicação: 2008
• Outros Autores: Mello, Flávio Luís de, Silva, Luiz Felipe Coutinho Ferreira da
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Boletim de Ciências Geodésicas
• Texto Completo: https://revistas.ufpr.br/bcg/article/view/11275
• topic: Rede Triangular Irregular; Interpolação; Padrão de Exatidão Cartográfica; Triangular Irregular Network (TIN); Interpolation; Cartographical Exactness Standard

To apply the linear model to interpolate attributes for 2D points, theattributes of three points ware weighted with their respective barycentriccoordinates. However, the finite arithmetic effects at the computation returnsbarycentric coordinates contaminated with numerical residuals that, despitetheir irrelevant dimensions that face the representable objects, it may influencethe system to make decisions involving values comparisons. In order to fixthis problem, tolerance limits were established around the theorical value, andthe processed values are attuned. This paper analyzes the influence fromattributes interpolation numerical precision over a computational environment.The limits for residuals produced by computational barycentric coordinatescalculus were defined. Those limits were chosen so that data imprecision didnot exceed it original cartographical documents precision limits, according tothe Padrão de Exatidão Cartográfica (PEC), under the most rigidclassification. The residuals found in tests were quite smaller than theprecision assured by the cartographic document used. This way, theestablished limits were reliable references to solve the purposed problem.