Calculation and Analysis of Typical Coastal Low-Tide Marks Based on Lidar Data

Coastal Zone is the current research hotspot. But it is difficult to accurately designate the inter-tidal coastal zone because the low-tide mark is underwater for a long time and difficult to be established. Light Detection and Ranging (Lidar) can quickly, directly and accurately detect elevation information of real surface and ground; The high-resolution aerial image synchronously accessed with Lidar can notably present characteristics of, so it is convenient for accurately locating and extracting features; we can acquire the average tide difference of coastal zone according to years of tidal information. With the support of geographic information system and remote sensing technology, this paper establishes a model for extracting the low-tide mark based on Lidar data and the high-resolution aerial image simultaneous received. The main contents of the model are: (1) Extract the average high-tide mark and water-mark from the high-resolution aerial image in ArcGIS; (2) Generate DEM using Lidar data, and then derive gradients from the generated DEM. (3) Calculate the average tide difference according to tidal information. Finally, based on the above three parameters, reckon the projected average low-tide mark position.