[GRASS-user] [GRASSLIST:1169] Flow accumulation revisited (MFD + cost surface)

GRASS GRASS user
1

So I'm in a bit of a quandary here -- I want to use a MFD flow algorithm,
but I want it used on a surface of precipitation (so the accumulation isn't
calculating "number of pixels", rather a "real" value). r.watershed allows
me to assign a surface value, but isn't MFD. Is anyone aware of any
algorithms that do both (use MFD and per-pixel values), either in GRASS or
Arc (or in some other package?) Thanks!

--j

--

Jonathan A. Greenberg, PhD
NASA Postdoctoral Researcher
NASA Ames Research Center
MS 242-4
Moffett Field, CA 94035-1000
Phone: 415-794-5043
AIM: jgrn3007
MSN: jgrn3007@hotmail.com

2

There are no modules for that in GRASS. r.terraflow uses a MFD
algorithm, but doesn't have any option for weighted flow accumulation.
I've requested the feature:
http://intevation.de/rt/webrt?serial_num=4863

If I remember correctly, ArcObject has a function called FlowDirection
or something (I forgot its name). Maybe, it's implemented in the raster
calculator.

Huidae Cho

On Tue, Aug 01, 2006 at 10:48:54AM -0700, Jonathan Greenberg wrote:

So I'm in a bit of a quandary here -- I want to use a MFD flow algorithm,
but I want it used on a surface of precipitation (so the accumulation isn't
calculating "number of pixels", rather a "real" value). r.watershed allows
me to assign a surface value, but isn't MFD. Is anyone aware of any
algorithms that do both (use MFD and per-pixel values), either in GRASS or
Arc (or in some other package?) Thanks!

--j

--

Jonathan A. Greenberg, PhD
NASA Postdoctoral Researcher
NASA Ames Research Center
MS 242-4
Moffett Field, CA 94035-1000
Phone: 415-794-5043
AIM: jgrn3007
MSN: jgrn3007@hotmail.com

3

On Tuesday 01 August 2006 10:48, Jonathan Greenberg wrote:

So I'm in a bit of a quandary here -- I want to use a MFD flow algorithm,
but I want it used on a surface of precipitation (so the accumulation isn't
calculating "number of pixels", rather a "real" value). r.watershed allows
me to assign a surface value, but isn't MFD. Is anyone aware of any
algorithms that do both (use MFD and per-pixel values), either in GRASS or
Arc (or in some other package?) Thanks!

--j

--

Jonathan A. Greenberg, PhD
NASA Postdoctoral Researcher
NASA Ames Research Center
MS 242-4
Moffett Field, CA 94035-1000
Phone: 415-794-5043
AIM: jgrn3007
MSN: jgrn3007@hotmail.com

Hi Jonathan,

Have you had a look at the r.sim.water modules ?

--
Dylan Beaudette
Soils and Biogeochemistry Graduate Group
University of California at Davis
530.754.7341