Method and application of using unmanned aerial vehicle for emergency investigation of single geo-hazard

In recent years, the unmanned aerial vehicle (UAV) began to be widely used in the emergency investigation of major 15 natural hazards in a large area, but less for the single geo-hazard. Based on a number of successful practices in the Three Gorges Reservoir Area, China, a complete UAV-based emergency investigation method of single geo-hazard is concluded. Firstly, a customized UAV system consisting of multi-rotor UAV subsystem, aerial photography subsystem, ground control subsystem and ground surveillance subsystem is described in detail. Then, the implementation process which includes four steps, i.e., indoor preparation, site investigation, site fast processing and applying, and indoor comprehensive processing and 20 applying is elaborated, and two investigation schemes including automatic and manual in the site investigation step are put forward. Moreover, some key techniques and methods, e.g., the ground controls points (GCPs) layout and measurement, the route planning, the flight and shooting process control, and the Structure from Motion (SfM) photogrammetry processing are explained. Finally, three applications are given. Practice shows that, using the UAV for emergency survey of single geo-hazard can not only greatly reduce the time, strength and risks of the on-site work, but also provide high-accuracy, high-definition 25 valuable information to well support the emergency treatment.