Use of Unmanned Aerial Vehicle as an Alternative to Generate Topographic Information

Unmanned Aerial Vehicles (UAVs) are becoming a very versatile technology tool in several application areas for devel-opment activities. Topography, as a fundamental area of engineering, provides information related to the three-dimen-sional location of points on the earth's surface. The objective of this work was to generate topographic information, us-ing UAV as a technological alternative to traditional techniques. The methodology consisted of planning and execution of two photogrammetric (lights with the EBEB SQ UAV, instrumented with the Sequoia multispectral camera. Five con-trol points were placed on the ground, georeferenced with a total station, used as control points in the processing of the (light images. The photographs captured in (light were processed by photogrammetry with PIX4Dmapper software on a desktop computer, with an Intel(R) Core (TM) i9-9900K CPU 3.60GHz processor and 32.0 GB of RAM. The photogrammetric flight results consisted of a total of 633 RGB photographs in a flight time of 36:27 minutes, for a coverage area of 57.7 ha. The processing quality report showed an accuracy of 2 mm in the georeferencing of the photographs with the control points. The photogrammetric processing was executed in a time of 48 minutes to generate Orthophotos, Digital Terrain Model (DTM) and three-dimensional point cloud. The generated products reached a spatial resolution of 5 cm/ pixel, with millimeter accuracies that allowed the management of secondary topographic information such as slope. The point cloud made it possible to classify the coverage in vegetation and soil, to estimate the height of the cotton crop canopy with an accuracy of 91%. As advantages of the UAV over traditional techniques for topographic surveys, the variety and precision of geospatial products and the optimization of times can be highlighted.