Extract river/stream centerlines from a DEM file and output as shapefile. Two approaches available:

Tiếng Việt

# Requires: QGIS installed (winget install OSGeo.QGIS_LTR)
extract_river_qgis.bat D:\data\dem.tif D:\data\river.shp
extract_river_qgis.bat D:\data\dem.tif D:\data\river.shp 100

Results are identical to running GRASS r.watershed + r.to.vect in QGIS GUI.

# Requires: Python 3 + rasterio, WhiteboxTools binary
extract_river_whitebox.bat D:\data\dem.tif D:\data\river.shp
extract_river_whitebox.bat D:\data\dem.tif D:\data\river.shp 500

• QGIS method: min watershed basin size in cells. Default: 100
• WhiteboxTools method: flow accumulation cell count. Default: auto (1% of max)

Higher threshold = fewer streams (main rivers only). Lower = more tributaries.

For QGIS method:

winget install OSGeo.QGIS_LTR

For WhiteboxTools method:

pip install rasterio
# Download WhiteboxTools from https://www.whiteboxgeo.com/download-whiteboxtools/
# Extract so that whitebox_tools.exe is at:
#   WhiteboxTools_win_amd64/WBT/whitebox_tools.exe

Copy config.example.txt to config.txt and set your paths:

# Path to qgis_process
QGIS_PROCESS=D:\QGIS 3.44.9\bin\qgis_process-qgis-ltr.bat

# Path to whitebox_tools.exe
WHITEBOX_TOOLS=D:\tools\WhiteboxTools\whitebox_tools.exe

# Default threshold (overridden by command-line argument)
# DEFAULT_THRESHOLD=100

If config.txt is not set, scripts will auto-detect installed tools.

1. GRASS r.watershed — A* priority-flood + MFD flow accumulation + stream extraction
2. GRASS r.to.vect — Convert stream raster to polyline shapefile with smoothing

1. Convert — Re-encode DEM to compatible GeoTIFF (removes PREDICTOR=3)
2. Fill Depressions — Remove spurious sinks
3. D8 Flow Direction — Compute flow direction per pixel
4. D8 Flow Accumulation — Count upstream contributing cells
5. Extract Streams + Vectorize — Threshold and convert to polyline shapefile

• GRASS GIS via QGIS qgis_process
• WhiteboxTools by Prof. John Lindsay (MIT License)
• rasterio for GeoTIFF I/O