r.width.funct

Calculates the Width Function of a watershed basin.

r.width.funct map=name image=image [--overwrite] [--verbose] [--quiet] [--qq] [--ui]

Example:

r.width.funct map=name image=image

grass.script.run_command("r.width.funct", map, image, overwrite=False, verbose=False, quiet=False, superquiet=False)

Example:

gs.run_command("r.width.funct", map="name", image="image")

Parameters

Command linePython (grass.script)

map=name [required]
    Distance to outlet map (from r.stream.distance)
image=image [required]
    Name for output graph file (png)
--overwrite
    Allow output files to overwrite existing files
--help
    Print usage summary
--verbose
    Verbose module output
--quiet
    Quiet module output
--qq
    Very quiet module output
--ui
    Force launching GUI dialog

map : str, required
    Distance to outlet map (from r.stream.distance)
    Used as: input, raster, name
image : str, required
    Name for output graph file (png)
    Used as: output, file, image
overwrite: bool, optional
    Allow output files to overwrite existing files
    Default: False
verbose: bool, optional
    Verbose module output
    Default: False
quiet: bool, optional
    Quiet module output
    Default: False
superquiet: bool, optional
    Very quiet module output
    Default: False

DESCRIPTION

r.width.funct produces the Width Function of a basin. The Width Function W(x) gives the number of the cells in a basin at a flow distance x from the outlet (it is also referred as distance-area function). It is important to underline the fact that the distance is not the euclidean one, but it is measured along the flowpath towards the outlet.

Input

Distance to outlet map: Input map, required. It is obtained by r.stream.distance (with the option: distance to outlet, flag -o).

Output plot: Path and name of the plot.

Output

It provides the quantiles of the area - distance distribution and the plot of the Width Function. In x axis is reported the distance and in y axis is the area.

EXAMPLE

North Carolina sample dataset example:

g.region raster=elevation -p

# Calculate flow direction
r.stream.extract elevation=elevation threshold=1000 \
direction=direction

# Create outlet point
echo "637304.924954,218617.100523" | v.in.ascii input=- sep=',' out=outlet

# Convert outlet point to raster
v.to.rast input=outlet type=point output=outlet use=cat

# Calculate distance to outlet map
r.stream.distance -o stream_rast=outlet \
direction=direction distance=dist2out

# Calculate width function
r.width.funct map=dist2out image=/tmp/my_basin

Dependencies

Matplotlib

REFERENCES

Rodriguez-Iturbe I., Rinaldo A. — Fractal River Basins, Chance and Self-Organization. Cambridge Press (2001)
In Italian: Di Leo M., Di Stefano M., Claps P., Sole A. — Caratterizzazione morfometrica del bacino idrografico in GRASS GIS (Morphometric characterization of the catchment in GRASS GIS environment), Geomatics Workbooks, n. 9 (2010)

AUTHORS

Margherita Di Leo (grass-dev AT lists DOT osgeo DOT org), Massimo Di Stefano, Francesco Di Stefano

SOURCE CODE

Available at: r.width.funct source code (history)
Latest change: Friday Feb 21 10:10:05 2025 in commit 7d78fe3