Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
r.water.outlet(1)	    GRASS GIS User's Manual	     r.water.outlet(1)

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   [--over-
       write]  [--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=nameA [required]
	   Name	of input drainage direction map

       output=nameA [required]
	   Name	for output watershed basin map

       coordinates=east,northA [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	water-
       shed.

       Input drainage direction	map indicates the "aspect" for each cell. Mul-
       tiplying	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 re-
       gion. The absolute value	of these negative cells	indicates  the	direc-
       tion of flow. This raster map is	generated from r.watershed.

       Output  raster map values of one	(1) indicate the watershed basin. Val-
       ues of zero (0) are not in the watershed	basin.

NOTES
       In the context of this program, a watershed basin  is  the  region  up-
       stream 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	repre-
       senting 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 threshold=5000 accumulation=accum_5K drainage=draindir_5K basin=basin_5K
       r.water.outlet input=draindir_5K	output=basin_A30 coordinates=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
       # report	outlet size in ha
       r.report	map=basin_A30 units=h

       Figure: Watershed draped	over flow accumulation

SEE ALSO
	 r.wateroutlet.lessmem	(addon),  d.where, r.basins.fill, r.watershed,
       r.topidx

AUTHOR
       Charles Ehlschlaeger, U.S. Army Construction Engineering	Research Labo-
       ratory

SOURCE CODE
       Available at: r.water.outlet source code	(history)

       Main  index  | Raster index | Topics index | Keywords index | Graphical
       index | Full index

       A(C) 2003-2020 GRASS Development	Team, GRASS GIS	7.8.4 Reference	Manual

GRASS 7.8.4						     r.water.outlet(1)

NAME | KEYWORDS | SYNOPSIS | DESCRIPTION | NOTES | EXAMPLE | SEE ALSO | AUTHOR | SOURCE CODE

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=r.water.outlet&sektion=1&manpath=FreeBSD+13.0-RELEASE+and+Ports>

home | help