崇明东滩水边线信息提取与潮滩DEM的建立

Waterline Extraction and DEM Reconstruction in Chongming Dongtan

由于潮滩范围广、变化频繁、缺乏常规的地形测量资料,给潮滩开发建设带来极大不便。以崇明东滩为实验区,依据长江口1999-2004年多时相遥感影像的光谱特征,对不同潮情的影像采用不同的波段提取水边线信息。同时根据实测4条高程剖面中的两条作为控制剖面获得水边线的高程,对具有高程信息的水边线利用不规则三角网方法构建了崇明东滩的数字高程模型(DEM)。并利用其它两条实测剖面对数字高程模型的精度进行了检验。结果表明,该方法减少了实测潮位资料缺乏及水边线提取误差对高程提取结果的影响,其均方根误差分别达到0.4 m和0.7 m。

Ground survey is restricted by the difficulty of access to wide-range and dynamic tidal flat. The lack of terrain handicaps exploration and development of tidal flat. In this article, we selected Chongming Dongtan as an experiment area. On the analysis of spectrum characteristics of multi--temporal remote sensing images （1999 -2004）, waterlines were extracted from different bands according to tidal conditions. The assignment of an elevation to the waterlines was performed according to two elevation survey profiles. The waterlines labeled elevation were used to construct TINs （Triangulated Irregular Networks）. Then an interpolation for each grid elevation was performed in accordance with the associated triangle. Finally, quantitative check of the result was examined according as the other two measurement profiles. The results indicate that the standard deviation of the approach is 0.4 m and 0. 7 m, respectively, which eliminates the effects of unavailable tidal height and discrepancy of waterlines on DEM precision.