Practical guidelines for performing UAV mapping flights

Uncrewed Aerial Vehicles (UAVs) have transformed remote sensing, offering unparalleled flexibility and spatial resolution across diverse applications. Many of these applications rely on mapping flights using snapshot imaging sensors, for creating 3D models of the area, or for generating orthomosaics from RGB, multispectral, hyperspectral or thermal cameras. Based on a literature review,  comprehensive guidelines for executing mapping flights for the different sensors are here formulated, addressing flight preparation, planning and execution. Key considerations in flight preparation and planning covered include sensor selection, flight altitude and GSD, flight speed, overlap settings, flight pattern, direction and viewing angle; considerations in flight execution include on-site preparations (GCPs, camera settings, sensor calibration and reference targets) as well as on-site conditions (weather conditions, time of the flights) to take into account. In all these steps, high-resolution and high-quality data acquisition needs to be balanced with feasibility constraints such as flight time, data volume and post-flight processing time. The formulated guidelines are based on literature consensus. However, knowledge gaps for mapping flight settings are identified, particularly in flight direction and for thermal imaging in general. These guidelines and identified knowledge gaps are useful to advance the harmonization of UAV mapping practices, promoting reproducibility and enhanced data quality across diverse applications.