Comparative Accuracy Assessment of Orthophotos Produced Using Different UAV and Photogrammetric Software

Abstract

Nowadays, the use of Unmanned Aerial Vehicles (UAVs) for producing maps of large areas is more advantageous in terms of both cost and time compared to Global Navigation Satellite Systems (GNSS). This study aims to produce orthophotos of a section of the Gebze Technical University Campus using aerial images obtained from two different UAVs and to compare their accuracy with GNSS measurements. A total of 77 points were established for georeferencing and accuracy control, measured in the TUREF/TM30 system using a GNSS device. Agisoft Metashape, Pix4D, and 3Dsurvey software were utilized to produce orthophotos of the study area. The positional accuracy of the orthophotos was assessed using checkpoints whose coordinates were determined by GNSS measurements. Agisoft Metashape achieved the best positional accuracy, while Pix4D software provided a smaller root mean square error on the Z-axis. The 3Dsurvey software had the longest processing time for the steps. The results obtained from studies conducted with all three software packages are within the acceptable limits defined by the Large Scale Map Information and Map Production Regulation. In conclusion, it has been determined that procedures typically performed by the GNSS/GPS can be effectively completed using UAVs, achieving high positional accuracy while saving time, reducing labor, and lowering costs. © 2025 Elsevier B.V., All rights reserved.