Hi list,
I'm trying to run r.terraflow on a very large DEM but I wander if it's
__too large__.
The region dimensions are:
ncol=141114
nrow=140487
Data type = CELL
The map is actually a reclass map of a raster that I imported using
r.external.
When I run r.terraflow I get:
r.terraflow elevation
Hi Daniel,
Try r.watershed with -m option in GRASS 7
(http://grass.osgeo.org/grass70/manuals/r.watershed.html)
For me, on Ubuntu 12.04, that worked well on a DEM of that size. But be
prepared to wait a couple of days for the result if you can not run it "in
memory"...
Cheers
Stefan
--
View th
I have never tried running r.terraflow on an integer raster,
> I know that it works on decimal rasters.
>
> -Thayer
>
>
>
> --
>
> Date: Mon, 12 Jan 2015 09:59:40 -0200
> From: Daniel Victoria
> To: grass
> Subject: [GRASS-user
a chance to make it
>> down hill, otherwise you can get streams going no where near where they do
>> in real life. I have never tried running r.terraflow on an integer raster,
>> I know that it works on decimal rasters.
>>
>> -Thayer
>>
>>
>>
>> --
&g
have a problem.
-Thayer
From: Daniel Victoria
To: Charlie Shobe
Cc: Thayer Young ; "grass-user@lists.osgeo.org"
Sent: Tuesday, January 13, 2015 9:17 AM
Subject: Re: [GRASS-user] r.terraflow on massive DEM
Ouch! That means that probably, the person who importe
oung ; "grass-user@lists.osgeo.org" <
> grass-user@lists.osgeo.org>
> *Sent:* Tuesday, January 13, 2015 9:17 AM
> *Subject:* Re: [GRASS-user] r.terraflow on massive DEM
>
> Ouch! That means that probably, the person who imported the data,
> converted it to integer with
o make it
>> down hill, otherwise you can get streams going no where near where they do
>> in real life. I have never tried running r.terraflow on an integer raster,
>> I know that it works on decimal rasters.
>>
>> -Thayer
>>
>>
>>
>> --
>>
>> Da
contained after the decimal point to allow the flow a chance to make it
>>> down hill, otherwise you can get streams going no where near where they do
>>> in real life. I have never tried running r.terraflow on an integer raster,
>>> I know that it works on decimal rasters.
ubject: Re: [GRASS-user] r.terraflow on massive DEM
Charlie,
I just downloaded some SRTM 1arc sec. from EarthExplorer. The data is supplied
in 3 different file types, GeoTIFF, DTED or BIL and they are all in Integer
values (Int16). No floating point elevation values.
Cheers
Daniel
On Tue, Ja
gt;>> Halpin, Toma, Urban, Vitter, Wickremesinghe Efficient Flow Computation on
>>>> Massive Grid Terrain Datasets Geoinformatica Volume 7 Issue 4, December
>>>> 2003
>>>> Pages 283 - 313 ). My mid-2014 computer runs at about twice the speed
>>
run it
> >>>> may take several days to finish, this is more than twice the size of
> the
> >>>> Washington State DEM that took the authors 33 hours in 2003 (Arge,
> Chase,
> >>>> Halpin, Toma, Urban, Vitter, Wickremesinghe Efficient Flow
> Computation on
> >>>> Massive Grid Terrain Datasets G
shed a try. If that does not work, I'll see if I can
>> >>> recompile.
>> >>>
>> >>> Thanks
>> >>> Daniel
>> >>>
>> >>> On Mon, Jan 12, 2015 at 9:22 PM, Thayer Young
>> >>> wrote:
>> >
and asking
> >> >>> me to
> >> >>> change the dimension_type and recompile.
> >> >>>
> >> >>> I'll give r.watershed a try. If that does not work, I'll see if I
> can
> >> >>> recompile.
> >>
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