[GRASS-user] upslope contributing areas

[Rainer M Krug]

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).
################


If you need it more accurate, maybe use *r.drain for each cell and add* the
flowpaths accordingly.

Cheers,

Rainer



>
> Francesco
>
>
>
> 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.*<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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