基于DEM的水系分维估算及其构造地貌意义研究——以雅砻江上游甘孜—德格段为例

Calculation of the Fractal Dimension Based on DEM and the Study of the Significance of Tectonic Landform—Take the Ganzi-Dege Section of Yalong River as an Example

基于数字高程模型(DEM),使用Arc GIS10.2软件提取了雅砻江上游甘孜—德格段的水系图,模拟网格法对研究区雅砻江及其支流玉隆河的分维值进行了估算,其值分别为1.1036和1.0169;通过对比集流阈值与分维值的关系确定了研究区内合理的集流阈值为5000.依据估算结果并结合前人研究资料,可以推断研究区流域地貌处于侵蚀发育的幼年期,河流以下蚀作用为主;区域地壳抬升导致研究区水系分维值偏大,但影响程度有待进一步研究;走滑型甘孜—玉树断裂带的存在导致研究区河道趋直,水系分维值偏小.

Based on DEM,the information of river networks of the Ganzi-Dege section of Yalong River basin is extracted by Arc GIS10. 2 software. Through the grid simulation method,the fractal dimension of the Yalong River and Yulong River is calculated. The fractal dimension of the Yalong River is 1. 1036 and the data of Yulong River is 1. 0169. According to the relationship between catchment threshold and fractal dimension,the reasonable catchment threshold is confirmed as 5000. According to the data of fractal dimension and predecessors＇ research data,the physiognomy of the study area is in infancy,and the down cutting is typical of the river. The crust uplift leads to the increase of fractal dimension,but the effect degree needs further research. The Ganzi-Yushu fault leads to the linearization of the watercourse and the decrease of fractal dimension.