[GRASS-dev] r.watershed - too many negatives in the flow accum

[Margherita Di Leo]

On Wed, May 28, 2014 at 10:54 AM, Margherita Di Leo <
dileomargherita at gmail.com> wrote:

> Hi,
>
> in nc dataset, running
>
> g.region rast=elev_lid792_1m -p
>
> r.watershed elevation=elev_lid792_1m \
> accumulation=elev_lid792_1m.acc \
> basin=elev_lid792_1m.basin \
> stream=elev_lid792_1m.stream \
> tci=elev_lid792_1m.tci \
> threshold=1000 \
> -m
>
> r.mapcalc "neg = if(elev_lid792_1m.acc < 0, 1, null())"
>
> the map of negatives (problematic areas) presents the pattern shown in the
> attached screen shot. To me it looks weird, usually i find problematic
> areas on the border of the map, because the water basin is cut and a part
> of it falls outside the region. In this case they cover most of the area,
> the central part included. Any insight?
>
>
> Here's the screen shot:
http://tinypic.com/view.php?pic=33b3fba&s=8#.U4WwNnV515E

grass is 7.0.0svn (r60523)



-- 
Best regards,

Dr. Margherita DI LEO
Scientific / technical project officer

European Commission - DG JRC
Institute for Environment and Sustainability (IES)
Via Fermi, 2749
I-21027 Ispra (VA) - Italy - TP 261

Tel. +39 0332 78 3600
margherita.di-leo at jrc.ec.europa.eu

Disclaimer: The views expressed are purely those of the writer and may not
in any circumstance be regarded as stating an official position of the
European Commission.
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