基于GIS的典型黄土小流域边界线分形特征研究

GIS-based fractal dimension values assessment of watershed boundary line of small watersheds of Loess Plateau

流域边界线是影响流域发育的重要地形控制线,尽管它不具有特征标度区间,但在不同的尺度上都有着精细的空间结构特征,具有重要的地理意义.论文以分形理论为指导,在借鉴现有河流与水系分形特征计算方法的基础上,结合GIS研究了典型黄土小流域边界线的分形特征值计算方法.以5m分辨率的高精度DEM数据为主要信息源,以陕西省绥德县韭园沟流域为典型研究样区进行了流域边界线的二维、三维分形特征值估算实验.实验结果表明流域边界线的三维分形特征值比二维分形特征值具有更好的区分度,可以较为客观地反映流域内部的地貌形态特征,今后应该进一步深化对流域边界线所蕴含的地学特征信息的科学认识.

Boundary line of watershed with absolutely sealed morphometry,which shows detail characteristics of structure with different scales,plays an important role in controlling the processes of landform evolution.It is so hard to find the special egienvalue intervals if we want to measure its boundary line.According to the fractal theory,this paper explores a method to calculate the fractal dimension values of watershed boundary line in 2D and 3D space.DEM data of this area with 5m resolution is used to calculate the 2D and 3D fractal dimension values of the boundary line to testify the validation of the method takeing the Jiu Yuan Gou watershed,Sui De county,Shan Xi Province as a case.The results show us more special and useful information of watershed are found when a watershed boundary line was calculated by 3D fractal values than bythat of 2D to depict the topographic characters for a watershed.So,the fractal dimensional values of a watershed boundary line by 3D should be further developed to understand the more important geographic information which lies in a watershed boundary line.