Study on the application of lidar technology and tidal model in determining island coastline

Abstract

Due to the geographical peculiarities of the sea islands, we often encounter the difficulty that some coastlines are hard to reach or to identify. Thus a specific measurement method cannot be implemented effectively, which affects the integrity and precision of island coastline surveying. In this paper, we use the digital elevation Model (DEM) by LIDAR date. However, The elevations acquired by an Airborne LIDAR system are ellipsoid heights, which is different from the National Vertical Datum 1985 in existing island coastline. For this reason, a regional quasi-geoid model is constructed with the geometric method, using the EGM2008 gravity field model and GPS/Leveling data. We manage to transform ellipsoid heights to normal heights from observations, and construct the DEM which is based on National Vertical Datum 1985. Finally island coastlines are extracted from the reference DEM and the associated tidal model and compared with that from GPS-RTK measurements.