Michael Vandesteen Silva Souto

Creation of a coastal evolution prognostic model using shoreline historical data and techniques of digital image processing in a GIS environment for generating future scenarios

ABSTRACT The process of coastal erosion is a global problem that impacts approximately 70% of coastal regions of the Earth. It causes loss of property, infrastructure, and biodiversity, besides generating major economic impacts. Therefore, the analysis and monitoring of coastal erosion is an issue that needs to be addressed. In this sense, remote-sensing data have been widely used in studies that evaluate the spatial and temporal changes of land use. In addition, the use of time series of satellite imagery applied in the investigation of changes in the Earth’s coverage and its spatio-temporal pattern has been proven as an extremely efficient approach. Thus, remote sensing and geoprocessing are effective techniques to obtain continuous and dynamic information from coastal regions at different levels and scales. In this context, the main objective of this work was to create a prognostic model for the generation of future scenarios, based on the analysis of the spatial-temporal changes of the shorelines from past decades to the present, having as the pilot area the coast of the municipality of Icapuí, in the State of Ceará, Northeastern Brazil. For that, Statistical Regression technique was used. In addition, the techniques of Digital Image Processing and the extraction of the modified normalized difference water index were used. As a result, the prognosis of coastal erosion was generated for the year 2021, based on the time series of the years 1985, 1991, 1997, 2003, 2009, and 2015. After the extrapolation process, the results were validated through the mean absolute error. Furthermore, through the Python programming language and the OpenCV library, a computational solution was implemented to be executed in a Geographic Information Systems environment that automated the process of generating future prognostic and the extraction of the shoreline in a shapefile format.

Short-time analysis of shoreline based on RapidEye satellite images in the terminal area of Pecém Port, Ceará, Brazil

ABSTRACT Coastal environments are highly dynamic and sensitive to interference and variations caused by the numerous natural and anthropogenic agents. The northern coast of Northeastern Brazil has undergone intense erosion in recent years. However, the construction of the Pecém Port modified the beach and shoreline features differently from the adjacent areas. This article describes using remote-sensing images integrated with a Geographic Information System to evaluate the sedimentary balance and morphological changes observed in the sandy beach area that was affected by the construction of Pecém Port. Two methods were applied to the RapidEye images to quantify the short-time changes that occurred on the coast. The Digital Shoreline Analysis System method showed that the beach width increased west to the port, which was calculated by the Change Polygon Approach determined by intersecting and uniting polygons to estimate the difference between the areas over time. The short-time analysis results showed changing coastal morphology, demonstrating that the anthropic interventions in the region are transforming significantly the natural elements that make up the region landscape. Between 2011 and 2014, the investigated beach stretch of approximately 3 km suffered an accretion process of more than 102,000 m2 over 3 years. The high spatial resolution of satellite images, digital processing imaging techniques and geostatistical methods were effective in this study, allowing understanding the recent changes in the area.

AVALIAÇÃO DA ACURÁCIA DO CÁLCULO DE VOLUME DE PILHAS DE REJEITO UTILIZANDO VANT, GNSS E LiDAR

Dentre as diversas tecnologias utilizadas para calculo do volume de materiais na mineracao, o Veiculo Aereo Nao Tripulado (VANT) e o Light Detecting And Ranging (LiDAR), surgem como alternativas rapidas e precisas, em comparacao com as tecnicas de topografia tradicionais como estacao total e Global Navigation Satellite System (GNSS). Diante destas novas tecnologias, este estudo avaliou a acuracia do calculo de volume, realizado por meio de Modelos Digitais de Terreno (MDTs), gerados a partir das tecnologias VANT, LiDAR e GNSS, em uma pilha de rejeito da extracao de calcario laminado, explorado para fabricacao de lajotas in natura, comercializado com o nome de “Pedra Cariri”, no municipio de Santana do Cariri, no Estado do Ceara. A avaliacao da acuracia foi realizada com base no metodo de testes de hipoteses, a partir da analise de tendencia e precisao, sendo os resultados classificados de acordo com o Padrao de Exatidao Cartografica dos Produtos Cartograficos Digitais (PEC-PCD). Como resultado, o modelo gerado a partir do VANT apresentou a melhor acuracia no calculo de volume da pilha de rejeito, objeto deste estudo, seguido pela modelagem obtida pelos levantamentos GNSS e LiDAR.