Scale Effect and Similarity Analysing of the Extracted River Networks Features Based on DEMs with Different Spatial Resolutions

¹ Key Laboratory of Environment Change and Resources Use in Beibu Gulf, Ministry of Education, Guangxi Teachers Education University, 175 Mingxiu East St., Nanning, 530001, China.
² School of Geography and Planning, Guangxi Teachers Education University, 175 Mingxiu East St., Nanning, 530001, China.

^* Corresponding author: crpp0104@163.com

Abstract

River networks are basic parameters in river studies and river management. Due to scale effect, most river networks are lack of certainty. We selected three leafy rivers from different climatic zone with an approximately proportional relation in basin area (1: 4.1: 19.9) to dig the scale effect and possible similarity. The result shows that the resolutions of DEM and drainage area threshold are two key parameters to extract river network features from DEM. The river lengths and densities of all extracted optimal river networks under the 6km² threshold values decrease with the spatial resolution. Based on 15 optimal river networks, the length ratio is similar to the area ratio, the density ratio is same (1: 1: 1), and the stream frequency ratio is near to 1: 1: 1. Bifurcation ratio values of all basins are closer to the average (4.75). These characteristics may imply that there is the similarity among rivers.