r.water.outlet - Watershed basin creation program.
(GRASS Raster Program)
r.water.outlet generates a watershed
basin from a drainage direction map (from
and a set of coordinates representing the
outlet point of watershed.
- 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
- Output map: Values of one (1) indicate the watershed
basin. Values of zero are not in the watershed basin.
- Input value: Easting value of outlet point.
- Input value: Northing value of outlet point.
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.
Charles Ehlschlaeger, U.S. Army Construction Engineering
Last changed: $Date: 2002/01/25 05:45:34 $