Wrapper for the awesome pysheds library for quick nested catchment delineation. Using a DEM as input, the functions provided here will return two GeoDataFrames: one detailing the stream network and another describing the corresponding catchment for each segment. Major thanks to Matt Bartos for his work on pysheds to make this possible.
Example:
import make_catchments
import folium
basins, branches = make_catchments.generate_catchments('path/to/dem.tif',acc_thresh=5000,so_filter=4)
Output:
Reading DEM...
Making flow accumulaton map...
Generating stream network...
Calculating pour points...
Generating 561 catchments...
Total runtime is 1.66 minutes
# Visualize output
gdf = basins.copy()
# separate by stream order
ones = gdf[gdf['Order']==1]
twos = gdf[gdf['Order']==2]
threes = gdf[gdf['Order']==3] # skip fours
# Map 'em!
cols = ['Index','Length','Relief','Order','Slope','AreaSqKm','LocalPP_X','LocalPP_Y','Final_Chain_Val','BasinGeo']
cols_branches = ['Index','Length','Relief','Order','Slope','geometry','LocalPP_X','LocalPP_Y','Final_Chain_Val']
m = branches[cols_branches].explore(color='black')
ones[cols].explore(m=m,color='blue',tiles='Stamen Terrain')
twos[cols].explore(m=m,color='purple',tiles='Stamen Terrain')
threes[cols].explore(m=m,color='yellow',tiles='Stamen Terrain')
folium.LayerControl().add_to(m)
m
The sample DEM provided in this repo is at 10m resolution. Function runtime will vary based on DEM size, resolution, and the thresholds used. Expect much longer runtimes if using a large DEM. To make the start up process easier, a .yml file is included. Main dependencies are: pysheds,rasterio, and geopandas.