Abstract
Currently, aerial photographs are acquired by unmanned aerial vehicles (UAVs) along preplanned flight routes, and a 3D model is constructed to investigate and measure the features of geological disasters. This work studies and evaluates the effectiveness and quality of three kinds of UAV routes used for landslide investigations by surveying a landslide in Luquan County, Kunming city, Yunnan Province. The advantages and disadvantages of 3D models based on the "horizontal round-trip route (HRr)", "terrain follow route (TFr)" and "inclined route (Ir)" methods were studied and compared through quality evaluation of the final products. The results show that the 3D models based on HRr and TFr have different degrees of distortion and blurring, while the 3D model based on Ir has a finer surface resolution, offers the best performance among the three routes, and can more truly capture the true surface of the survey features. Correspondingly, the checkpoint accuracies of the HRr, TFr, and Ir methods are 0.155 m, 0.064 m and 0.033 m, respectively, of which the 3D model based on Ir is the most accurate. This research indicate that inclined routes have better applicability in the investigation and monitoring of landslides.