calculating river slope

[David Harbor]

Dear Grass Users
Does anyone out there know of a GRASS routine or mapcalc statement that will
compute the slope of rivers?  The r.slope.aspect doesn't work because of the
very low slopes.  I think one would have to first define the pixels covering
the channels and then look up and downstream for the change in elevation over a
much greater distance.
Thanks in advance.
David Harbor
Washington and Lee University

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GIS Lab / Geology Department / Wahsington and Lee University / Lexington VA 244
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reply to:  grass at gilberty.geology.wlu.edu  or to  David Harbor <harbor at wlu.edu>