基于SPOT遥感影像的九段沙潮沟信息提取及分维研究

INFORMATION EXTRACTION AND FRACTAL DIMENSIONS BASED ON SPOT REMOTE SENSING IMAGE FOR TIDAL CHANNELS IN JIUDUAN SHAOL

以长江口九段沙为研究区,应用灰度形态学提取了九段沙湿地的潮沟信息,并对提取出的潮沟信息分区域采用网格法进行了分维研究,得出了九段沙不同区域潮沟的分维值,并对分维值进行了比较与分析。比较发现,九段沙不同区域的分维值,上沙最大,下沙次之,中沙最小。而在不同区域的不同岸段中,处于上沙北部沿岸的潮沟分维值大于上沙其它地区;处于中沙、下沙西北-东南沿岸的潮沟分维值分别大于中沙、下沙的其它地区。这主要与它们所处地理位置水动力条件不同有关。另外也计算了九段沙南岸与北岸的分维值,发现南岸的分维值要大于北岸,这与其发育时间、水动力条件和长江口深水航道工程等有一定联系。

Taking tidal channels in the Jiuduan Shaol in Changjiang （Yangtze） River mouth as a research case, information of which was extracted with Gray morphology and fractal dimensions were studied using grid method. The fractal dimension values were determined in different zones of the shoal, and the results were compared and analyzed. We find that the fractal dimension values can be schemed from large to small as Shangsha （upper shoal）, Xiasha （western shoal）, and Zhongsha （middle shoal）. For banks located in the same zone, the fractal dimension value of the North Bank in Shangsha was larger than other parts. For the river-banks in northwestern-southeastern coast of Zhongsha and Xiasha, their fractal dimensions were larger than others’ in the same zone, which can be attributed to the local hydraulic dynamics condition and geological setting. In addition, thefractaldimension values of the North Bank and South Bank were calculated, showing that the fractal dimension of the South Bank was larger than that of the North Bank, which is due to the development stage, hydraulic dynamics condition, and the deep-water channel project to a certain degree.