Abstract: Traditionally, information on coastal erosion and deposition is acquired by field surveying, using one-dimensional (1D) or 2D indices, not 3D expression of coastal morphology change. This article shows 5-m resolution high-precision DEMs (digital elevation models ) on Wuzhizhou Island using two periods of airborne Lidar point cloud data acquired by the South China Sea Airborne Detachment of China Marine Surveillance. In combination with synchronously acquired aerial images, 0.45m resolution DOMs (digital orthophoto maps) are created for this area based on the above DEM models. We also execute supervised classification and overlay analysis using DOMs to extract information on coastal erosion and deposition. These erosion and deposition patches appear alternately near the sandy coast. Combining DEMs and coastal erosion/deposition object polygons, we extract geometry, shape, surface, and volume attributes of these 12 polygons, such as area, perimeter, compact index, average slope difference, average aspect difference, average curvature difference, total volume change, etc. The analysis results provide 3D multi-view expression of coastal morphology change, aiming to offer a new research method for coastal resources management and planning.

Key words: Lidar, Wuzhizhou Island, coastal erosion and deposition, quantitative analysis