Avaliação de modelos digitais de elevação para análise espacial de bacias hidrográficas

• Autor(a) principal: Scárdua, Marcelo Dan
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/5786
• topic: Hydrography; Geographic Information Systems; Watersheds - Delimitation; Hidrografia; Sistemas de informação geográfica; Bacias hidrográficas - Delimitação; Recursos Florestais e Engenharia Florestal; 630

This study aimed to assess digital elevation models (DEMs) from different database in order to identify the ones that best perform watersheds delineation. We used three types of data sources of DEMs: a) DEMI: from the IBGE, obtained by the interpolator Top To Raster in ArcGIS b) DEMA: from ASTER GDEM, a Sensor from the National Aeronautics and Space Administration (NASA), and c) DEMT: from the Topodata project, a result of the refinement of SRTM, conducted by the National Institute for Space Research (INPE), all with a spatial resolution of 30 meters. The DEMA and DEMT were acquired directly from the internet. The DEMI was elaborate from cartographic data of IBGE, at 1:50,000 scale, using the contours lines (CN) with vertical intervals of 20 meters and the hydrography map. The DEMs were used in their original forms and refined to obtain DEMs with greater hidrological consistency. The original DEMs (DEMI, DEMA and DEMT) were used directly for the delimitation of BHs, using the extension ArcHydro (AH) in ArcGIS® 10.1, while the refined DEMs (DEMIr, DEMAr and DEMTr) were pre-processed using the algorithm Agree, for further watershed delineation using. A reference watershed delimitation reference was made to compare with the automatic delimitation obtained with the six options of DEMs studied. The reference delimitation was performed manually in GIS (ArcGIS), using IBGE maps, containing CN, hydrography and elevation points. The assessment of the delimitations was performed qualitatively through visual analysis, and quantitatively, by the method of divergent areas. In other words, the increase and decreases of areas in relation to the reference delimitation. Also it was compared the numerical hydrography (HN) generated with and without refinement. It showed the effectiveness of the algorithm Agree, observing a high similarity between the refined hydrography and the reference hydrography. In the comparison of HN without refinement, it was verified that the one obtained from the DEMT showed better performance than that obtained from the DEMA. At of the delimitations without refinement, the one derived from the DEMI was the closest to the reference delimitation, followed by the derived from DEMT and DEMA. When comparing the delimitations of the refined DEMs, the best one was the DEMIr; however, the second and third position were inverted, being the DEMAr better than DEMTr. Consistency hydrological changes concerning the delimitation of basins can be better evidenced when analyzed in watersheds located within the watershed