Extraction and analysis of gully nodes based on geomorphological structures and catchment characteristics: A case study in the loess plateau of North Shaanxi province
摘要
A gully node is the intersection of gully or river networks,which reflects the geomorphological structure and hydrological characteristic of the gully area.Effective extraction and analysis of gully nodes are essential to understand the spatial structure,morphology,and hydrological characteristic of a catchment.An algorithm based on high resolution digital elevation model(DEM) data is proposed for extracting gully nodes together with the classification method.The algorithm and method are tested in an experimental area on the Loess Plateau of North Shaanxi Province.The numbers of gully nodes of different order gullies and the flow accumulation value associated with each gully node are obtained.The relationship between the numbers of gully nodes in any given order class and the sum of corresponding flow accumulation values is obtained using a mathematical model.The variations in the spatial distribution of flow accumulation values in different geomorphological regions are studied using the arithmetic progression classification method.Finally,the spatial regularity of geomorphological features is preliminary discussed.