Orthophoto Production and Accuracy Analysis with UAV Photogrammetry

Abstract

Undoubtedly, Unmanned Aerial Vehicles (UAV) are one of today’s most functional technology products. In recent years, UAVs integrated with different sensors and transformed into harmony with advanced technology are developing rapidly and used in different applications to obtain geographical data. With UAV photogrammetry, images of target areas can be obtained quickly, at low cost, with high accuracy, and up to date. In addition to the advantages and success of existing methods for orthophoto production in large areas with classical photogrammetry, it is observed that the accuracy of these methods decreases in detecting changes in geometric properties and especially in small-scale areas. For this reason, the ability to obtain geometric accuracy with the desired precision, which is of great importance in orthophoto production with UAV photogrammetry, has made it the reason for preference over classical methods. In this study, autonomous flights were carried out with DJI Mavic-2 Pro UAV in the selected pilot region, and orthophoto, Digital Elevation Model (DEM), and Digital Terrain Model (DTM) were produced as a result of processing the images obtained. In order to determine the geometric accuracy of the orthophoto, its coordinates were determined by the CORS-GPS method, and ten ground control points (GCP) were used. As a result of the accuracy analysis of the produced orthophoto, the spatial accuracy in the ΔY direction is ±6.9 cm, the spatial accuracy in the ΔX direction is ±7.8 cm, and the spatial accuracy in the ΔZ direction is ±10.3 cm.