v.stream.network - GRASS GIS manual

Note: This document is for an older version of GRASS GIS that has been discontinued. You should upgrade, and read the current manual page.

NAME

v.stream.network - Build a linked stream network: each link knows its downstream link

KEYWORDS

vector, stream network, hydrology, geomorphology

SYNOPSIS

v.stream.network

v.stream.network --help

v.stream.network map=name [upstream_easting_column=string] [upstream_northing_column=string] [downstream_easting_column=string] [downstream_northing_column=string] [tostream_cat_column=string] [--help] [--verbose] [--quiet] [--ui]

Flags:

--help: Print usage summary
--verbose: Verbose module output
--quiet: Quiet module output
--ui: Force launching GUI dialog

Parameters:

map=name [required]: Vector stream network from r.stream.extract; Or data source for direct OGR access
upstream_easting_column=string: Upstream easting (or x or lon) column name; Default: x1
upstream_northing_column=string: Upstream northing (or y or lat) column name; Default: y1
downstream_easting_column=string: Downstream easting (or x or lon) column name; Default: x2
downstream_northing_column=string: Downstream northing (or y or lat) column name; Default: y2
tostream_cat_column=string: Adjacent downstream segment category; Zero (0) indicates off-map flow; Default: tostream

DESCRIPTION
NOTES
REFERENCES
SEE ALSO
AUTHOR

DESCRIPTION

v.stream.network populates the attribute table of a river network built by r.stream.extract with five new columns that define the nodes and links within a river network. These are (default names given):

x1, y1: upstream coordinates
x2, y2: downstream coordinates
tostream: category number of the next stream; is equal to 0 if the stream flows off of the map

Any stream-like network will work, but the lines need to be connected. In terms of graph theory, a tree and forest are supported. Behavior for a cyclic graph is undefined.

NOTES

streams is a set of vector lines that is generated by r.stream.extract. It is recommended to be built as follows (Python code):

# Choose elevation map and threshold
elevation = srtm
threshold = 1E6 # [m**2], minimum catchment size = 1 km**2
# Build a map of cell areas: pick one of these
# km2 is more intuitive, but 1 km2 is the threshold for the smallest
# threshold catchment size
r.mapcalc('cellArea_meters2 = '+str(reg.nsres)+' * '+str(reg.ewres), overwrite=True)
r.mapcalc("cellArea_km2 = cellArea_meters2 / 10^6", overwrite=True)

# Use r.watershed to build a drainage basin with units of length**2
# instead of arbitrary units (cells)
r.watershed(elevation=elevation, flow='cellArea_meters2', accumulation='drainageArea_m2', drainage='drainageDirection', stream='streams', threshold=thresh, flags='s', overwrite=True)
# Note that this will include areas of negative (i.e. offmap) flow accumulation

# Build watershed network using r.stream.extract: single-flow-direction (SFD)
print "Building drainage network"
r.stream_extract(elevation=elevation, accumulation='drainageArea_m2', threshold=thresh, d8cut=0, mexp=0, stream_raster='streams', stream_vector='streams', direction='draindir', overwrite=True)

REFERENCES

Ng, G-H. Crystal, Andrew D. Wickert, Lauren D. Somers, Leila Saberi, Collin Cronkite-Ratcliff, Richard G. Niswonger, and Jeffrey M. McKenzie. "GSFLOW–GRASS v1. 0.0: GIS-enabled hydrologic modeling of coupled groundwater–surface-water systems." Geoscientific Model Development 11 (2018): 4755-4777. DOI 10.5194/gmd-11-4755-2018

AUTHOR

Andrew D. Wickert

SOURCE CODE

Available at: v.stream.network source code (history)

Latest change: Saturday Jul 29 18:49:49 2023 in commit: d683353f77e13263c38f870a8f21f966b80bea51