r.water.outlet <main> GRASS Reference Manual<main> r.water.outlet



NAME
     r.water.outlet - Watershed basin creation program.
     (GRASS Raster Program)

SYNOPSIS
     r.water.outlet
     r.water.outlet help
     r.water.outlet drainage=name basin=name easting=value
	  northing=value

DESCRIPTION
     r.water.outlet generates a watershed basin from a drainage
     direction map (from r.watershed or r.water.aspect) and a set
     of coordinates representing the outlet point of watershed.

OPTIONS
     drainage
	  Input map: drainage direction.  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 map is generated from either
	  r.watershed or r.water.aspect.

     basin
	  Output map: Values of one (1) indicate the watershed
	  basin.  Values of zero are not in the watershed basin.

     easting
	  Input value: Easting value of outlet point.

     northing
	  Input value: Northing value of outlet point.

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.

     It is usually a good idea for the user to "find" the stream
     channel of the desired basin.  If the user runs
     r.water.accum, r.water.swale with a small swale threshold,
     and d.where on the resulting map, the user can pinpoint the
     exact location of the outlet point with ease.





GRASS 5.0beta6	      GRASS Development Team			1






r.water.outlet <main> GRASS Reference Manual<main> r.water.outlet



SEE ALSO
     r.watershed, r.water.aspect, r.water.accum, r.water.swale,
     r.water.basin, d.where

AUTHOR
     Charles Ehlschlaeger, U.S. Army Construction Engineering
     Research Laboratory
















































2		      GRASS Development Team	   GRASS 5.0beta6