2024 Volume 80 Issue 22 Article ID: 23-22005
In road management during the snowy season, it is important to properly determine changes in snow depth on slopes next to roads. UAV-SfM surveying, which has been increasingly used in recent years, is an efficient method for measuring snow depth, but it has been pointed out that it is difficult to stably and permanently establish multiple ground reference points on snow-covered slopes, which is necessary to accurately superimpose the positions of point clouds during the snow-free and snow-covered seasons. In this study, we focused on the differences in positioning methods of UAVs and the number of ground reference points to be set up on slopes, and verified their measurement accuracy. As a result, it was confirmed that the measurement error of snow depth could be suppressed to +6.4 cm (8%), which is practicable for snow depth measurement, under the following conditions: (1) a UAV equipped with RTK is used, (2) set the ground pixel size to the equivalent of 1 cm when shooting, and (3) at least two ground reference points are installed for SfM analysis. This result indicates that the UAV-SfM surveying system can improve the efficiency of ground reference point placement during the snowy season.
