DESCRIPTION
r.stream.slope calculates local downstream elevation change
and local downstream minimum and maximum curvature.
OPTIONS
- direction
- Flow direction: name of input direction map produced by r.watershed or
r.stream.extract. If r.stream.extract output map is used, it only has non-NULL
values in places where streams occur. NULL (nodata) cells are ignored, zero and
negative values are valid direction data if they vary from -8 to 8 (CCW from
East in steps of 45 degrees). Direction map shall be of type CELL values. Region
resolution and map resolution must be the same.
- elevation
- Elevation: name of input elevation map or any other map we want to calculate.
Map can be of type CELL, FCELL or DCELL. It is not restricted to resolution of
region settings like direction.
- difference
- Output downstream elevation difference: difference between elevation of current
cell and downstream cell. Shall always be positive. Negative values show, that
current cell is pit or depression cell. Module is prepared to be used with
elevation but can be also used to calculate local difference of any feature
along watercourses in slope subsystem. In that way elevation map must be
replaced by map we want to calculate. If we use different map than elevation,
rest of parameters have no sense to calculate
- gradient
- Output downstream gradient: Downstream elevation difference divided by
distance.
- maxcurv
- Output maximum linear curvature along watercourse. Calculated along watercourse
between highest upstream cell, current cell and downstream cell (there can be
only one or no downstream cell but more than on upstream)
- mincurv
- Output minimum linear curvature along watercourse.
Calculated along watercourse between lowest upstream cell, current cell and
downstream cell (there can be only one or no downstream cell but more than on
upstream)
EXAMPLE
g.region -p -a rast=elevation
r.watershed elevation=elevation threshold=10000 drainage=dirs stream=streams
r.stream.slope dir=dirs elevation=elevation difference=downstream_elev_difference \
gradient=downstream_gradient maxcurv=downstream_maxcurv mincurv=downstream_mincurv
SEE ALSO
r.watershed,
r.stream.extract,
r.stream.order,
r.stream.basins,
r.mapcalc,
AUTHOR
Jarek Jasiewicz, Adam Mickiewicz University, Geoecology and Geoinformation
Institute.
Last changed: $Date: 2014-03-27 19:51:13 +0100 (Thu, 27 Mar 2014) $