[GRASS-user] upslope contributing areas

[Markus Metz]

On Thu, Oct 13, 2011 at 9:41 AM, Rainer M Krug <r.m.krug at gmail.com> wrote:
>
>
> On Thu, Oct 13, 2011 at 9:04 AM, Francesco Mirabella <mirabell at unipg.it>
> wrote:
>>
>> Hello,
>> and thanks for your fast replies,
>> yes, the final result which I'd like to get is a river profile along which
>> the values of the upslope contributing areas can be plotted on a separate y
>> axis.
>> In order to get this I suppose I should be able to "cat
>> river_long_profile_ascii | r.profile a_raster_map_containing_the
>> upslope_areas" which can provide values in square meters or square km or
>> whatever.
>> Do you know if such a raster map can be obtained from a dem?
>
> Possibly r.flow could help here - in the manual:
>
> ################
> There are three possible output maps which can be produced in any
> combination simultaneously: a vector map flout of flowlines, a raster map
> lgout of flowpath lengths, and a raster map dsout of flowline densities
> (which are equal upslope contributed areas per unit width, when multiplied
> by resolution).
> ################
>

Another possibility to get total upslope contributing area for each
cell is the flow accumulation output of r.watershed and r.terraflow.

Upslope contributing areas for arbitrary points can be determined with
r.stream.basins, or one point after another with r.water.outlet. These
modules use drainage direction produced by r.watershed as input.

HTH,

Markus M

>>
>>
>> Rainer M Krug wrote:
>>>
>>> It depends on what the OP was looking for - it sounds to me that he is
>>> looking for a kind of "dynamic" approach, where one can determine the
>>> upslope drainage area for an arbitrary location. Unfortunately, I don't have
>>> a solution, but would be quite interested in the answer.
>>>
>>> Cheers,
>>>
>>> Rainer
>>>
>>> On Thu, Oct 13, 2011 at 8:36 AM, Johannes Radinger <jradinger at gmx.at
>>> <mailto:jradinger at gmx.at>> wrote:
>>>
>>>    Hello Francesco,
>>>
>>>    you could use something like the AddOn r.stream.basin
>>>    (http://grass.osgeo.org/wiki/R.stream.*)
>>>    to delineate the basins. Every basin gets a unique number.
>>>    Afterwards you can just query how
>>>    many cells do have a certain number.
>>>
>>>    best regards!
>>>    Am 13.10.2011 <tel:13.10.2011> um 08:20 schrieb Francesco Mirabella:
>>>
>>>     > Hi list,
>>>     > does anyone know if there is a way to compute the upslope
>>>    drainage contributing areas along a stream?
>>>     >
>>>     > thanks for your help!
>>>     > Francesco
>>>     >
>>>     >
>>>     >
>>>     >
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>>>
>>>
>>> --
>>> Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation
>>> Biology, UCT), Dipl. Phys. (Germany)
>>>
>>> Centre of Excellence for Invasion Biology
>>> Stellenbosch University
>>> South Africa
>>>
>>> Tel :       +33 - (0)9 53 10 27 44
>>> Cell:       +33 - (0)6 85 62 59 98
>>> Fax (F):       +33 - (0)9 58 10 27 44
>>>
>>> Fax (D):    +49 - (0)3 21 21 25 22 44
>>>
>>> email:      Rainer at krugs.de <mailto:Rainer at krugs.de>
>>>
>>> Skype:      RMkrug
>>>
>
>
>
> --
> Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation Biology,
> UCT), Dipl. Phys. (Germany)
>
> Centre of Excellence for Invasion Biology
> Stellenbosch University
> South Africa
>
> Tel :       +33 - (0)9 53 10 27 44
> Cell:       +33 - (0)6 85 62 59 98
> Fax (F):       +33 - (0)9 58 10 27 44
>
> Fax (D):    +49 - (0)3 21 21 25 22 44
>
> email:      Rainer at krugs.de
>
> Skype:      RMkrug
>
>
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