[GRASS-user] Re: problem using r.watershed

[Filipe Silva Dias]

Thanks. Out of curiosity and tried with Grass 7 with -m (and 30 m
resolution) and I obtained this error message:

r.watershed -m elevation=DemPT2 at Grass7 threshold=10000
stream=streams
SECTION 1 beginning: Initiating Variables. 5 sections total.
SECTION 1a: Mark masked and NULL cells
SECTION 1b: Determining Offmap Flow.
SECTION 2: A* Search.
SECTION 3: Accumulating Surface Flow with MFD.
SECTION 4: Watershed determination.
SECTION 5: Closing Maps.
ERROR: Rast_make_random_colors: min (1) > max (0)
Subprocess failed with exit code 1
category information for [streams] in [Grass7] missing or invalid



On Sun, Mar 25, 2012 at 11:49 AM, Markus Metz <
markus.metz.giswork at googlemail.com> wrote:

> On Sun, Mar 25, 2012 at 12:30 PM, Filipe Silva Dias
> <filipesdias at gmail.com> wrote:
> > I switched the resolution from 30x30 to 100x100 and now it works. Problem
> > solved.
> >
> >
> > On Sun, Mar 25, 2012 at 11:12 AM, Filipe Silva Dias <
> filipesdias at gmail.com>
> > wrote:
> >>
> >> I'm using GRASS 6.4.2 and I'm on Windows 7
> >>
> >>
> >> On Sun, Mar 25, 2012 at 11:11 AM, Filipe Silva Dias
> >> <filipesdias at gmail.com> wrote:
> >>>
> >>> Dear all
> >>>
> >>> I'm trying to run r.watershed on a ASTER DEM (with the size of
> Portugal)
> >>> but I'm getting this error:
> >>>
> >>> r.watershed elevation=DemPt at ETRS89 stream=stream
> >>> threshold=10000
> >>> SECTION 1a (of 5): Initiating Memory.
> >>> ERROR: G_malloc: unable to allocate 1515173064 bytes at init_vars.c:134
> >>> Subprocess failed with exit code 1
> >>> category information for [stream] in [ETRS89] missing or invalid
> >>>
> >>> What am I doing wrong?
> >>>
> As you figured out already, the region, i.e. number of cells was too
> large. In order to run r.watershed with that region (Portugal at 30m
> resolution) on Windows, you would need GRASS 7 and run r.watershed
> with the -m option.
>
> Markus M
>
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