DESCRIPTION

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 raster=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

See also r.streams.* modules wiki page.

AUTHOR

Last changed: $Date$