Tidal land Digital Elevation Model Remote Sensing based on High-Resolution Tidal level Grid
【摘要】：Waterline method and tidal level grid were investigated to construct Digital Elevation Model (DEM) of tidal land of mud. Based on a series of China property Beijing-1(BJ-1) small satellite image data, which are kept in the achieves and can cover an area of 600 km×600 km, a series of waterlines were automatically extracted with improved accuracy using "region grow integrating edge information" considering different tidal conditions of the mud tidal land. A high precision tidal level grid of 1.2′×1.2′ of China coastal sea of Bohai was firstly applied to establish spatial joining with each waterline at each time when the satellite was imaging. This fine regional ocean tide model around China sea was based on POM model and blending assimilation approach. Then the assignment of elevations to the waterlines were performed by spatial joining between this tidal level grids and waterlines. Based on these waterline points, the triangulated irregular network (TIN) of tidal land topography was built. Then the grid DEM was generated by TIN. Different from other methods, waterline is not considered a contour line but the elevation of waterline points were assigned according to the high precise tidal level grid, so a precise DEM was acquired. Compared with the results of in situ GPS RTK surveying of three profiles, the mean values of elevation absolute error were less than 0.2 m, and the overall standard error was 0.188 m. This accuracy will meet the DEM mapping acquirement of 1:200 000, and some important area of 1:50 000.