Avaliação da acurácia vertical de modelos digitais de elevação derivados de diferentes sensores orbitais para Belém-PA.

Abstract

Located in Coastal Zone and with more than 1 million habitants, Belém is a metropolis that has been suffering a big expansion in last years, under the scarcity of infrastructure and suitable studies to an expansion like Brazil's south and southeast cities. Among the cartographic products derived from orbital remote sensing, stand out the Digital Elevation Models (DEMs), that offers elevation data for any environments, including the coastal environments with their expressive dynamics. As a consequence of the particularities related to the Belém's region and the Amazon Coastal Zone (ACZ), the present research proposes to assessing the vertical accuracy of free-use DEMs to for Belém's region, through an exploratory errors analysis having as reference coordinates data set of tridimensional points that were obtained by a high precision Airborne Light Detection and Ranging (LIDAR) and determine the absolute and relative accuracy, using the estimator Root Mean Square Error (RMSE) and in accordance to the Brazilian Cartographic Accuracy Standard for Digital Cartographic Products (PEC- PCD). The selected DEMs was the Shuttle Radar Topography Mission (SRTM) GL1, SRTM/X-SAR DEM, SRTM GL1 Alaska Satellite Facility (ASF) Up Sampled, TOPODATA, ALOS Global Digital Surface Model AW3D30 and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Digital Elevation Model (GDEM) 2, generated by SAR Interferometry and Stereoscopic Models. The stereoscopic AW3D30 DEM achieved RMSE equals to 4.01 m, the best ones, and the others achieved RMSE between 4.53 and 14.72 m, focusing at the worst RMSE to ASTER GDEM 2. In addition, when applying the PEC-PCD, it was verified adherence to normality for the DEMs GL1 and GL1 ASF Up Sampled and existence of bias except in the AW3D30, the compatibles scales were between 1:25.000 and 1:50.000, varying between categories B, C and D. When considering the A class tolerances, the SRTM/X-SAR DEM and TOPODATA obtained at a scale of 1:50.000 while the other DEMs obtained 1: 100.000 and 1: 250.000 scales. The research showed that the production of more accurate MDEs and the frequent cartographic data uptades of the region are relevant, supporting the studies in the region of Belém and ACZ. Keywords: Cartography. Digital Elevation Models. SAR Interferometry. Stereoscopy. Vertical Accuracy. Amazon Coastal Zone.