This is the command r.water.outletgrass that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator
PROGRAM:
NAME
r.water.outlet - Creates watershed basins from a drainage direction map.
KEYWORDS
raster, hydrology, watershed
SYNOPSIS
r.water.outlet
r.water.outlet --help
r.water.outlet input=name output=name coordinates=east,north [--overwrite] [--help]
[--verbose] [--quiet] [--ui]
Flags:
--overwrite
Allow output files to overwrite existing files
--help
Print usage summary
--verbose
Verbose module output
--quiet
Quiet module output
--ui
Force launching GUI dialog
Parameters:
input=name [required]
Name of input drainage direction map
output=name [required]
Name for output watershed basin map
coordinates=east,north [required]
Coordinates of outlet point
DESCRIPTION
r.water.outlet generates a watershed basin from a drainage direction map and a set of
coordinates representing the outlet point of watershed.
Input drainage direction map indicates the "aspect" for each cell. Multiplying positive
values by 45 will give the direction in degrees that the surface runoff will travel from
that cell. The value -1 indicates that the cell is a depression area. Other negative
values indicate that surface runoff is leaving the boundaries of the current geographic
region. The absolute value of these negative cells indicates the direction of flow. This
raster map is generated from r.watershed.
Output raster map values of one (1) indicate the watershed basin. Values of zero (0) are
not in the watershed basin.
NOTES
In the context of this program, a watershed basin is the region upstream of an outlet
point. Thus, if the user chooses an outlet point on a hill slope, the resulting map will
be a thin silver of land representing the overland slope uphill of the point.
EXAMPLE
A watershed in the North Carolina sample dataset region:
g.region raster=elev_lid792_1m -p
# the watershed outlet position should be placed on a stream (from
# accumulation map):
r.watershed elev_lid792_1m thresh=5000 accum=accum_5K drain=draindir_5K output=basin_5K
r.water.outlet input=draindir_5K output=basin_A30 coord=638740.423248,220271.519225
d.mon wx0
d.rast map=accum_5K
d.rast map=basin_A30
# overlay with transparency
r.colors map=basin_A30 color=grey
d.his h=accum_5K i=basin_A30
Figure: Watershed draped over flow accumulation
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