Using GRASS for stream-network extraction and basins delineation

Methodological procedure described in:

Amatulli, Giuseppe, et al. “Hydrography90m: A new high-resolution global hydrographic dataset.” Earth System Science Data Discussions 2022 (2022): 1-43.

mkdir -p /home/user/my_SE_data/exercise
cd /home/user/my_SE_data/exercise
jupyter lab /home/user/my_SE_data/exercise/grass_newproject.ipynb

The first step towards modeling hydrological features is delineating a comprehensive hydrography network. DEMs at different spatial resolutions allow for the identification of stream channels, using a variety of flow-routing algorithms. Such algorithms are based on the observation that water follows the steepest and shortest route along a relief, and accumulates in valleys, lowlands, flat areas and depressions. Several algorithms have been proposed for stream network routing. These algorithms proceed in several stages: determining flow directions, resolving depressions and flat areas, and finally, calculating flow accumulation.