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Selecting Liaodong Bay as study area, comparing errors of various interpolation methods and then choosing the best interpolation method, this thesis generates high-precision DEM for the seabed. Then we analysis the terrain factors and explore the regular of change and evolution of the terrain. The main content includes:1. Process multi-beam dataOn the basis of CARIS system, the original multi-beam data are processed as following steps: navigation signal edited, sound velocity corrected, draught corrected, tidal level corrected,data combined, data detection and so on. Completed the above steps, the depth chart of the sea can be drawn, and the analysis of the terrain of the seabed can be continued.2. Compare the precision of various interpolation methods, explore the the best method to generate DEMThis thesis compares the errors of the test points after interpolation in the methods of Inverse Distance Weighted(IDW), Spline interpolation, Kriging Interpolation and converse TIN to regular grid. Ultimate, we find IDW method has the highest accuracy and generate the DEM of seabed using the IDW method.3. Extract and analyse terrain factorsOn the basis of DEM data,we extract the microcosmic terrain factors such as slope degree and slope direction, and macroscopic terrain factors such as water depth, surface coarseness,surface rolling and surface incision,and so on. Analyzing those factors,we explore the characteristic and regulars of the factors.4. Explore the characteristic of the evolution of seabedThrough landform drawing and profile analysis, we get the main characteristic of the sand ridges.Comparing with the library of sand ridges in 1998,we explore the change and regular of the sand ridges. The result demonstrates that sand ridges trends to degradation.
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