基于BJ-1影像和高分辨率潮汐网格的潮滩DEM构建

Tidal Land Digital Elevation Model Establishment Based on Beijing-1 Small Satellite Image and High-resolution Tidal Level Grid

平缓潮滩的测绘受到潮汐和淤泥的双重影响,难以进行大区域的人工作业。探讨利用序列遥感影像构建潮滩DEM的技术方法。基于多时相BJ-1小卫星自动提取水边线,利用中国近海高分辨率潮位网格,与卫星过境时刻的水边线进行空间关联与内插,生成带有高程值的系列水边点,并以此来构建潮滩地形三角网,最后生成格网潮滩DEM。与现场RTK验证的三个剖面的高程相比,其高程绝对误差均值小于0.2m。结果表明,应用中分辨率遥感影像进行淤泥质潮滩地形反演可以达到一定比例尺的制图精度。

The topographic measurement of muddy tidal flat is restriced by the difficulty of access to the complex, wide-range and dynamic tidal conditions. Then the waterline detection method （WDM） has the potential to investigate the morphodynamics quantitatively by utilizing large archives of satellite images.The study is based on a series of Beijing -1 （B J -1） small satellite image data, and a series of waterlines are automatically extracted considering different tidal conditions of the muddy tidal land. A high precision tidal level grid DEM of China coastal sea of Bohai is firstly applied to establish spatial joining with each waterline at each time when the satellite is imaging.Compared with the results of insitu GPS RTK surveying of three profiles,the mean values of elevation absolute error are less than 0.2m. Results show that DEM construction with middle resolution remote sensing images might be an effective tool for coastal zone mapping with certain scale.