长江岸线与岛屿演化的空间分形研究——以江苏段为例

FRACTAL ANALYSIS OF SPATIAL PATTERN AND EVOLVEMENT OF BANK-LINES AND ISLANDS OF THE YANGTZE RIVER ——A CASE STUDY OF JIANGSU REACHES

根据分形理论,采用网格和面积周长两种分形维数计算方法,以遥感卫星影像为主要数据源,在GIS支持下,计算了长江江苏段5个时相的岸线和岛屿空间分布的分形维数,探讨了其中所隐含的地理含义,认为长江江苏段岸线和江中岛屿都具有分形性质,分维数的变化可以反映它们的稳定程度;比较了不同量测方法、不同标度、不同比例尺下长江江苏段岸线的长度,认为岸线长度的值是不确定的。

According to the fractal theory, the appropriate methods are used to compute the fractal dimensions of bank-line and spatial distribution of island with aid of GIS and RS in five different years.i.e.,1969,1985,1994,1997 and 2002. The parameters to compute the fractal dimensions used in this study include grid and area-perimeter. The software used in the study mainly includes Arc/Info, ArcView and SPLUS. According to the result and analysis, some meaningful conclusions are drawn as follows:First, there exits fractal characteristics, and the change of fractal dimensions shows the stability degree of bank-lines of the Yangtze River and islands located in the Yangtze River; Second, there exits some correlation between the fractal dimension and the number of islands. But the quantitative relation determined because of non-enough samples.Third, the length of bank-line of the Yangtze River is not certain.Fourth, some things about bank-line, including development and management of bank-line and bracer engineering of the Yangtze River bank impact the stability degree of bank-lines to a some extent.