Basic Terrain Analysis is in Processing Toolbox of QGIS and it has many output results, like Channel Network, Drainage Basins, Valley Depth, etc. I just want to get Channel Network among these results. And as you know, this processing progress takes too much time and it can only deals with small area. So I am wondering if I can rewrite this processing tool. I went to the official website(http://www.saga-gis.org/saga_tool_doc/6.0.0/ta_compound_0.html ) to find out the detail description of this tool. But it didn't show me the way to implement this tool. So does anyone know how to implement basic terrain analysis. Or does anyone know the detail description of this tool.