[GRASS-user] Average raster value of the upslope contributing area,

GRASS GRASS user
1

Dear users,

my deal is to calculate a raster of the sediment delivery ratio like
explained here:
http://data.naturalcapitalproject.org/nightly-build/invest-users-guide/html/sdr.html#sediment-delivery-ratio

moreover I need to calculate, for each cell, the average of a raster (C
factor) of the upslope contributing area.
take a look to these image to better explication:
http://data.naturalcapitalproject.org/nightly-build/invest-users-guide/html/_images/connectivity_diagram.png

How can I do that?
Thanks
Pierluigi

--

________________________________________________________________________
Ing. Pierluigi De Rosa (PhD)
Studio Associato GFOSSERVICES

2

Hi Pierluigi,

I think here you could use the tool r.watershed (https://grass.osgeo.org/grass70/manuals/r.watershed.html)
with your underlying DEM as input. This tool will provide you an accumulation map with increasing values in
downstream direction.

I am not exactly sure if this is your task, but if you provide an input map for ‘flow’ with values for each cell that represents
the actual cell size than the output accumulation map output is your upslope contributing area. If you
use another input map for ‘flow’ (e.g. sediment input per cell) than the output will be the accumulated sediment
in downstream direction. Subsequently you can use r.mapcalc to divide both maps to get the ratio
of sediment delivery per unit upslope contributing area.

I hope that helps?!

cheers,
Johannes

···

On Thu, Dec 17, 2015 at 11:29 AM, Ing. Pierluigi De Rosa <pierluigi.derosa@gfosservices.it> wrote:

Dear users,

my deal is to calculate a raster of the sediment delivery ratio like
explained here:
http://data.naturalcapitalproject.org/nightly-build/invest-users-guide/html/sdr.html#sediment-delivery-ratio

moreover I need to calculate, for each cell, the average of a raster (C
factor) of the upslope contributing area.
take a look to these image to better explication:
http://data.naturalcapitalproject.org/nightly-build/invest-users-guide/html/_images/connectivity_diagram.png

How can I do that?
Thanks
Pierluigi

–

Ing. Pierluigi De Rosa (PhD)
Studio Associato GFOSSERVICES

grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

3

Hi Johannes,

perhaps you procedure could be correct.
Let’me try and I will notify my progress
Pierluigi

···

On Thu, Dec 17, 2015 at 11:29 AM, Ing. Pierluigi De Rosa <pierluigi.derosa@gfosservices.it> wrote:

Dear users,

my deal is to calculate a raster of the sediment delivery ratio like
explained here:
http://data.naturalcapitalproject.org/nightly-build/invest-users-guide/html/sdr.html#sediment-delivery-ratio

moreover I need to calculate, for each cell, the average of a raster (C
factor) of the upslope contributing area.
take a look to these image to better explication:
http://data.naturalcapitalproject.org/nightly-build/invest-users-guide/html/_images/connectivity_diagram.png

How can I do that?
Thanks
Pierluigi

–

Ing. Pierluigi De Rosa (PhD)
Studio Associato GFOSSERVICES

grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user