Multi-scale structure of channel network in Jiuyuangou drainage basin

Digital Terrain Analysis (DTA) is an important way for interpreting and understanding natural landform. Scale, an essential subject for realizing pattern and process in nature, is a fundamental issue in DTA. River basins are the basic natural system of many hydrologic phenomena. Multi-scale analysis of channel network can explore structural characteristic and spatial pattern of drainage basin, make basis on drainage evolution and provide suitable scale for drainage research. This paper investigates the structural characteristic of channel network under multiple scales and finds out accurate critical points of scales. Two kinds of lacunarity algorithms, i.e. gliding box algorithm and 3TLQV are adopted. Several conclusions can be drawn from the experiments. Firstly, there are five scale patterns in WE direction and three scale patterns in NS direction in channel network of Jiuyuangou drainage basin. Each scale pattern indicates a kind of hydrologic process. Secondly, anisotropy is between WE and NS direction in channel network. Thirdly, at each scale examined there's fractal pattern and fractal dimensions in different scales have little difference. Fourthly, an effective way for interpreting spatial pattern under different scales is put forward and it can be used for other network, such as ridgelines, population distribution etc.