Potentialities of the Digital Elevation Model (DEM) generated by Unmanned Aerial Vehicle (UAV) in mapping beach areas
UAV, Positional Accuracy, Coastal Mapping
In all sedimentary areas exposed to waves there are beaches. They are among the most dynamic physical systems on the earth's surface, occurring on coasts where there is enough sediment for waves to deposit above sea level. As a result of the dynamics of these systems, numerous shorelines of urbanized beaches suffer from coastal erosion and accretion. This fact causes a series of related problems, the most relevant being those arising from the interaction between unplanned occupation and areas subject to natural processes of coastal erosion. Thus, the proper monitoring of the erosion/accretion dynamics so that the expected stages in the variation of both morphology and the coastline itself can be predicted, directly implies the degree of success of actions related to coastal management focused on the beaches. In order to identify, monitor and classify the beach environment, it is necessary to obtain four-dimensional information (X, Y, Z, t), from the Digital Elevation Model (MDE), among others, information that was traditionally generated from topographic surveys in the field or from satellite images. As a way to streamline these works, the professional and academic market, supported by scientific studies, economic viability and agility, is increasingly making use of the technology of Unmanned Aerial Vehicles (UAVs) associated with on-board sensors, whose efficiency is proven in several studies from different areas. In addition, the results obtained also point to the potential of using the UAV tool in studies of coastal morphodynamics, which can be used both for qualitative analyzes (oblique photographs) and for quantitative analyzes (vertical photographs). In this context, the main objective of this work is to evaluate the positional accuracy of products generated from flights performed with the same aircraft (Phantom 4 Pro) over the same stretch of beach in the city of Ilhéus-Ba, on the same day, using the same technical parameters, however varying the heights and processing methods as the number of control and verification points to be considered. The results will be evaluated according to the Brazilian positional accuracy standard (Decree 89.817/84 combined with ET-ADGV / ET-CQDG).