This tool extracts thalwegs from DEMs through the following steps: 1) Filling depression, 2) Calculating flow direction, 3) Calculating flow accumulation, and finally select the DEM cells with flow accumulations larger than a user-specified threshold.
This first step depends on richdem to fill depression. The algorithm used is "Priority-Flood+Epsilon" from "C Barnes, R., Lehman, C., Mulla, D., 2014. Priority-flood: An optimal depression-filling and watershed-labeling algorithm for digital elevation models. Computers & Geosciences 62, 117–127." doi:10.1016/j.cageo.2013.04.024.
Installation (python 3.9 or 3.10 is recommended):
- Utility library developed by Dr. Zhengui Wang:
pip install git+https://github.com/wzhengui/pylibs.git(You may need to install mpi4py seperately if the pip commond failed)
- pyDEM:
pip install git+https://github.com/schism-dev/RiverMeshTools.git#subdirectory=pyDEM(You may need to install GDAL manually if the pip command failed)
Download sample applications here and extract using the command
tar xvf pyDEM_Samples.tarSee this section in the SCHISM manual for the most up-to-date tutorial.