Hi Don
I think you can solve this using grass 7 (you can download it from
http://grass.osgeo.org/download/software/). This version includes a new
option for r.cost that copies the value of the nearest cell. You can
solve the problem using
r.mapcalc "streamH=if(isnull(stream.thin),null(),FD)"
r.cost -k input=area.one output=dtv start_rast=streamH nearest=nearestH
nearestH will contains the elevation of the nearest stream
Best regards
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El 21/03/14 23:47, MacQueen, Don escribió:
I'm stating with a DEM (named FD).
First I find streams:
r.watershed elevation=FD stream=stream
r.thin input=stream output=stream.thin
Then, for each point on the DEM, I need
The distance to the nearest point in a stream
The elevation difference to the stream point
I can get the distance by gollowing the example "Computing a distance map"
in Neteler & Mitasova's GRASS book:
r.mapcalc area.one=1
r.cost -k input=area.one output=dtv start_rast=stream.thin
So far so good, and the results make sense
But I would very much appreciate suggestions for the elevation difference.
I have been looking at various r.* routines, such as r.drain, but haven't
yet found a solution. I have very little experience with raster analysis.
(and in fact, I'm using the R package spgrass6 to manage the above steps)
Thanks
-Don
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