limitations of r.stream.order

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limitations of r.stream.order

Carlos Henrique Grohmann de Carvalho-2
Hi there.

Is there any limitation on the size of rasters that r.stream.order can handle? I'm trying to run it for a large area (rows: 8640, cols: 6480) and it gives me several of these warnings:

WARNING: Stream network may be too dense...

and it doesn't produce the desired output.

best

Carlos


--
Prof. Carlos Henrique Grohmann
Institute of Geosciences - Univ. of São Paulo, Brazil
- Digital Terrain Analysis | GIS | Remote Sensing - 

http://orcid.org/0000-0001-5073-5572
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Re: limitations of r.stream.order

Carlos Henrique Grohmann de Carvalho-2
I forgot to mention some important info, sorry.

I'm running this on Mac OSX 10.8 (Mountain Lion), GRASS 6.4 from William Kyngesburye.

Carlos



On Sun, Apr 21, 2013 at 2:16 PM, Carlos Grohmann <[hidden email]> wrote:
Hi there.

Is there any limitation on the size of rasters that r.stream.order can handle? I'm trying to run it for a large area (rows: 8640, cols: 6480) and it gives me several of these warnings:

WARNING: Stream network may be too dense...

and it doesn't produce the desired output.

best

Carlos


--
Prof. Carlos Henrique Grohmann
Institute of Geosciences - Univ. of São Paulo, Brazil
- Digital Terrain Analysis | GIS | Remote Sensing - 

http://orcid.org/0000-0001-5073-5572
________________
Can’t stop the signal.



--
Prof. Carlos Henrique Grohmann
Institute of Geosciences - Univ. of São Paulo, Brazil
- Digital Terrain Analysis | GIS | Remote Sensing - 

http://orcid.org/0000-0001-5073-5572
________________
Can’t stop the signal.

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Re: limitations of r.stream.order

Rich Shepard
In reply to this post by Carlos Henrique Grohmann de Carvalho-2
On Sun, 21 Apr 2013, Carlos Grohmann wrote:

> Is there any limitation on the size of rasters that r.stream.order can
> handle? I'm trying to run it for a large area (rows: 8640, cols: 6480) and
> it gives me several of these warnings: WARNING: Stream network may be too dense...

Carlos,

   Try adjusting the threshold in r.watershed that you use to create the
accumunlation map. All the r.basin.* series are sensitive to threshold size,
so everywhere you specify a threshold value try increasing it -- greatly --
until you get a number that works for your needs.

Rich

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Applied Ecosystem Services, Inc.   |
<http://www.appl-ecosys.com>     Voice: 503-667-4517      Fax: 503-667-8863

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Re: limitations of r.stream.order

Carlos Henrique Grohmann de Carvalho-2
Well, working with subsets of the area worked, It was indeed a RAM limitation.

best

Carlos




On Sun, Apr 21, 2013 at 6:09 PM, Rich Shepard <[hidden email]> wrote:
On Sun, 21 Apr 2013, Carlos Grohmann wrote:

I need a detail a bit more compatible with topo maps at 1:1.000.000 scale,
which I can get if I use a threshold of 25-50 cells. But then, of course,
I have a more dense drainage network, and it seems that r.stream.order is
having problems dealing with such dense networks.

Carlos,

  Well, if your workstation has sufficient memory for all the calculations
then I've no idea what to suggest. The largest area with which I've worked
is 125 square miles (however many square kilometers that is) and I can
delineate too many drainage basins with 4G RAM.

  Perhaps working in smaller chunks of area and recombining results will do the
job. Otherwise, others with more expertise will need to offer suggestions.

Regards,


Rich

--
Richard B. Shepard, Ph.D.          |   Integrity - Credibility - Innovation
Applied Ecosystem Services, Inc.   |
<http://www.appl-ecosys.com>     Voice: <a href="tel:503-667-4517" value="+15036674517" target="_blank">503-667-4517      Fax: <a href="tel:503-667-8863" value="+15036678863" target="_blank">503-667-8863




--
Prof. Carlos Henrique Grohmann
Institute of Geosciences - Univ. of São Paulo, Brazil
- Digital Terrain Analysis | GIS | Remote Sensing - 

http://orcid.org/0000-0001-5073-5572
________________
Can’t stop the signal.

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