[GRASS-user] Use of r.watershed

Hello All,

I am new to GRASS but have been using GIS (mainly ESRI products) for quite a few years. I am trying to learn how to use GRASS to carry out hydrology related analyses. Currently, I am trying to use the r.watershed command to delineate the basins for a watershed. My question is, how long would you expect it to take to run? I am wondering if I am doing it wrong or if it just takes longer than I would expect. The DEM is about 170MB TIFF before I import it to GRASS. I have tried to run it a few times using different options, each time letting it run for 3 - 4 hours before killing it. I have tried both the -m and -4 flags. Any input would be appreciated.

How many rows and columns are in the input map? Also include the exact
command line statement you use to run the program.

Sincerely, chuck

Chuck Ehlschlaeger, Geospatial Science Consultant
PERTAN GROUP, http://pertan.com/
c.ehlschlaeger@insightbb.com, 309-255-2727
http://chuck.ehlschlaeger.info/

-----Original Message-----
From: grass-user-bounces@lists.osgeo.org
[mailto:grass-user-bounces@lists.osgeo.org] On Behalf Of
hydro@hydromodeling.com
Sent: Wednesday, January 23, 2008 7:15 AM
To: grass-user@lists.osgeo.org
Subject: [GRASS-user] Use of r.watershed

Hello All,

I am new to GRASS but have been using GIS (mainly ESRI products) for
quite a few years. I am trying to learn how to use GRASS to carry out
hydrology related analyses. Currently, I am trying to use the
r.watershed command to delineate the basins for a watershed. My
question is, how long would you expect it to take to run? I am
wondering if I am doing it wrong or if it just takes longer than I
would expect. The DEM is about 170MB TIFF before I import it to
GRASS. I have tried to run it a few times using different options,
each time letting it run for 3 - 4 hours before killing it. I have
tried both the -m and -4 flags. Any input would be appreciated.
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grass-user@lists.osgeo.org
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Chuck,

Thanks for your reply. The DEM has 8,627 rows and 10,270 columns. The command line statement I used is:

r.watershed el=fill th=400 ac=fac ba=basins st=str

I have also tried using the -m and -4 flags placed after the r.watershed part.

Thanks,

Matt

Quoting Charles Ehlschlaeger <c.ehlschlaeger@insightbb.com>:

How many rows and columns are in the input map? Also include the exact
command line statement you use to run the program.

Sincerely, chuck

Chuck Ehlschlaeger, Geospatial Science Consultant
PERTAN GROUP, http://pertan.com/
c.ehlschlaeger@insightbb.com, 309-255-2727
http://chuck.ehlschlaeger.info/

-----Original Message-----
From: grass-user-bounces@lists.osgeo.org
[mailto:grass-user-bounces@lists.osgeo.org] On Behalf Of
hydro@hydromodeling.com
Sent: Wednesday, January 23, 2008 7:15 AM
To: grass-user@lists.osgeo.org
Subject: [GRASS-user] Use of r.watershed

Hello All,

I am new to GRASS but have been using GIS (mainly ESRI products) for
quite a few years. I am trying to learn how to use GRASS to carry out
hydrology related analyses. Currently, I am trying to use the
r.watershed command to delineate the basins for a watershed. My
question is, how long would you expect it to take to run? I am
wondering if I am doing it wrong or if it just takes longer than I
would expect. The DEM is about 170MB TIFF before I import it to
GRASS. I have tried to run it a few times using different options,
each time letting it run for 3 - 4 hours before killing it. I have
tried both the -m and -4 flags. Any input would be appreciated.
_______________________________________________
grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

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8:12 PM

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Version: 7.5.516 / Virus Database: 269.19.9/1238 - Release Date: 1/22/2008
8:12 PM

Markus,

I am running GRASS version 6.2.2 on Ubuntu 7.10. I am at work right now and don't have access to the machine, but I am pretty sure about the GRASS version. If I am wrong I will post a correction when I get home.

Matt

Quoting Markus Neteler <neteler@osgeo.org>:

Matt,

please also post to the list which GRASS version on which
operating system you use.

Markus

On Jan 23, 2008 3:51 PM, <hydro@hydromodeling.com> wrote:

Chuck,

Thanks for your reply. The DEM has 8,627 rows and 10,270 columns.
The command line statement I used is:

r.watershed el=fill th=400 ac=fac ba=basins st=str

I have also tried using the -m and -4 flags placed after the r.watershed part.

Thanks,

Matt

Quoting Charles Ehlschlaeger <c.ehlschlaeger@insightbb.com>:

> How many rows and columns are in the input map? Also include the exact
> command line statement you use to run the program.
>
> Sincerely, chuck
>
> Chuck Ehlschlaeger, Geospatial Science Consultant
> PERTAN GROUP, http://pertan.com/
> c.ehlschlaeger@insightbb.com, 309-255-2727
> http://chuck.ehlschlaeger.info/
>
> -----Original Message-----
> From: grass-user-bounces@lists.osgeo.org
> [mailto:grass-user-bounces@lists.osgeo.org] On Behalf Of
> hydro@hydromodeling.com
> Sent: Wednesday, January 23, 2008 7:15 AM
> To: grass-user@lists.osgeo.org
> Subject: [GRASS-user] Use of r.watershed
>
> Hello All,
>
> I am new to GRASS but have been using GIS (mainly ESRI products) for
> quite a few years. I am trying to learn how to use GRASS to carry out
> hydrology related analyses. Currently, I am trying to use the
> r.watershed command to delineate the basins for a watershed. My
> question is, how long would you expect it to take to run? I am
> wondering if I am doing it wrong or if it just takes longer than I
> would expect. The DEM is about 170MB TIFF before I import it to
> GRASS. I have tried to run it a few times using different options,
> each time letting it run for 3 - 4 hours before killing it. I have
> tried both the -m and -4 flags. Any input would be appreciated.
> _______________________________________________
> grass-user mailing list
> grass-user@lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/grass-user
>
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.516 / Virus Database: 269.19.9/1238 - Release Date: 1/22/2008
> 8:12 PM
>
> No virus found in this outgoing message.
> Checked by AVG Free Edition.
> Version: 7.5.516 / Virus Database: 269.19.9/1238 - Release Date: 1/22/2008
> 8:12 PM
>

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