NAME
v.stream.network - Build a linked stream network: each link knows its downstream linkKEYWORDS
vector, stream network, hydrology, geomorphologySYNOPSIS
v.stream.network
v.stream.network --helpv.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 cat (0 = offmap flow)
- Default: tostream
Table of contents
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
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)
SEE ALSO
r.stream.extract v.stream.orderREFERENCES
None (yet)AUTHOR
Andrew D. WickertSOURCE CODE
Available at: v.stream.network source code (history)
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