Avaliação de algoritmos e modelos digitais de elevação para extração automática da drenagem / Automatic drainage network extraction using digital elevation models

AUTOR(ES)

Darcy Carolina Jiménez Fernández

FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

30/05/2011

RESUMO

This work is an evaluation of automatic processes for drainage extraction from Digital Elevation Models (DEM), as related to different data sources, terrain types, algorithms and operation parameters. SRTM, Topodata and GDEM data of four (4) watersheds with distinct geomorphometries were processed through six (6) different flow algorithms (D8, Rho8, Dinf, Mf, KRA e DEMON), operated with different caption area thresholds. The effect of DEM pre-processing procedures was also evaluated. Two mapped drainage networks, in the State of São Paulo (SP), at the 1:50,000 scale, and in the State of Rondônia (RO), at the 1:100,000 scale, were used as reference data source. All tests involved reference and experimental networks, which were superimposed for visual analyses and correspondence assessments, also quantified with Geographical Information System (GIS) resources, to evaluate errors and positional issues. Analyses of the drainage networks from reference data and experimental results were compared as a functional evaluation of the digital extraction methodologies. The main results showed: drainage networks resulting from automatic processes were apparently suitable for relatively generalized scales, but unsatisfactory when observed at the scales compatible to the perception of features in the respective DEM, requiring adjustments by other methodologies; distinct performance of algorithms among watersheds; and a relation between caption area threshold and drainage density; and, in plain relief of Amazonia, the general low performance of all methodologies, except when using Topodata after preprocessed with 3x3 mean filter. Best performances were achieved with DEMON algorithm. The study on threshold parameter evidenced the need for stratified processing in geomorphometrically similar areas.

ASSUNTO(S)

relevo mde área de captação drainage flow routing algorithms relief drenagem algoritmos de fluxo dem catchment area

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