[GRASS-user] r.damflood question

Codrina_Maria_Ilie · August 28, 2017, 8:53pm

Hi all,

I have been trying to run GRASS7 module r.damflood using the following datasets [https://drive.google.com/drive/folders/0B2Yx_1shUSx3VThlY3BrV1JyWjg?usp=sharing], with this command:

r.damflood --overwrite --verbose elev=dem lake=water_depth dambreak=dam_breach manning=manning tstop=3 deltat=1 h=b_depth vel=b_vel hmax=b_mwd vmax=b_mwv imax=b_mi wavefront=b_wf

To make it easier, the lake has a constant depth.

As far as I can understand, the rasters should be correctly built, but the outputs of r.damflood are obviously wrong (rasters with nodata or one category = 0; at second 1 the depth raster is half the lake's size (s00.png, s01.png)and at second 2, it completely disappears).

During the processing, I get the Courant-Friedrich-Lewy stability condition warning message.

If I try to chose as computational method for initial velocity estimation, uniform drop in of lake or small dam breach, I get the following error "ERROR: Don't find the dambreak - Please select a correct map or adjust the computational region".

Does anyone have an idea what could be the reason of these results, please? Any suggestion would be highly appreciated.

Cheers,
Codrina

annakrat · August 28, 2017, 9:05pm

Hi,

On Mon, Aug 28, 2017 at 4:53 PM, Codrina Maria Ilie
<codrina@geo-spatial.org> wrote:

Hi all,

I have been trying to run GRASS7 module r.damflood using the following
datasets
[https://drive.google.com/drive/folders/0B2Yx_1shUSx3VThlY3BrV1JyWjg?usp=sharing],
with this command:

r.damflood --overwrite --verbose elev=dem lake=water_depth
dambreak=dam_breach manning=manning tstop=3 deltat=1 h=b_depth vel=b_vel
hmax=b_mwd vmax=b_mwv imax=b_mi wavefront=b_wf

To make it easier, the lake has a constant depth.

As far as I can understand, the rasters should be correctly built, but the
outputs of r.damflood are obviously wrong (rasters with nodata or one
category = 0; at second 1 the depth raster is half the lake's size (s00.png,
s01.png)and at second 2, it completely disappears).

During the processing, I get the Courant-Friedrich-Lewy stability condition
warning message.

If I try to chose as computational method for initial velocity estimation,
uniform drop in of lake or small dam breach, I get the following error
"ERROR: Don't find the dambreak - Please select a correct map or adjust the
computational region".

Does anyone have an idea what could be the reason of these results, please?
Any suggestion would be highly appreciated.

Your water_depth should have 0 instead of nulls, I think that's the
problem in your case. The stability condition warning probably means
you should reduce your time step, on the other hand, it will take more
time.

Anna

Cheers,
Codrina

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mlennert · August 28, 2017, 9:29pm

Le Mon, 28 Aug 2017 17:05:01 -0400,
Anna Petrášová <kratochanna@gmail.com> a écrit :

Hi,

On Mon, Aug 28, 2017 at 4:53 PM, Codrina Maria Ilie
<codrina@geo-spatial.org> wrote:
> Hi all,
>
> I have been trying to run GRASS7 module r.damflood using the
> following datasets
> [https://drive.google.com/drive/folders/0B2Yx_1shUSx3VThlY3BrV1JyWjg?usp=sharing],
> with this command:
>
> r.damflood --overwrite --verbose elev=dem lake=water_depth
> dambreak=dam_breach manning=manning tstop=3 deltat=1 h=b_depth
> vel=b_vel hmax=b_mwd vmax=b_mwv imax=b_mi wavefront=b_wf
>
> To make it easier, the lake has a constant depth.
>
> As far as I can understand, the rasters should be correctly built,
> but the outputs of r.damflood are obviously wrong (rasters with
> nodata or one category = 0; at second 1 the depth raster is half
> the lake's size (s00.png, s01.png)and at second 2, it completely
> disappears).
>
> During the processing, I get the Courant-Friedrich-Lewy stability
> condition warning message.
>
> If I try to chose as computational method for initial velocity
> estimation, uniform drop in of lake or small dam breach, I get the
> following error "ERROR: Don't find the dambreak - Please select a
> correct map or adjust the computational region".
>
> Does anyone have an idea what could be the reason of these results,
> please? Any suggestion would be highly appreciated.

Your water_depth should have 0 instead of nulls, I think that's the
problem in your case. The stability condition warning probably means
you should reduce your time step, on the other hand, it will take more
time.

r.null null=0 gets rid of the stability condition warning as well.

However, I don't know much about this module, but I'm a bit surprised
by your DEM: IIUC, it's level is lower in the entire dam lake area than
in the valley below. Also: is it normal that your water depth is
constant all over the lake ?

Moritz

Codrina_Maria_Ilie · August 30, 2017, 8:44am

Hi Anna,

You were perfectly right!
I changed from null to 0 and it works.

Thank you!
Codrina

On 29/08/2017 00:05, Anna Petrášová wrote:

Hi,

On Mon, Aug 28, 2017 at 4:53 PM, Codrina Maria Ilie
<codrina@geo-spatial.org> wrote:

Hi all,

I have been trying to run GRASS7 module r.damflood using the following
datasets:
[https://drive.google.com/drive/folders/0B2Yx_1shUSx3VThlY3BrV1JyWjg?usp=sharing],
with this command:

r.damflood --overwrite --verbose elev=dem lake=water_depth
dambreak=dam_breach manning=manning tstop=3 deltat=1 h=b_depth vel=b_vel
hmax=b_mwd vmax=b_mwv imax=b_mi wavefront=b_wf

To make it easier, the lake has a constant depth.

As far as I can understand, the rasters should be correctly built, but the
outputs of r.damflood are obviously wrong (rasters with nodata or one
category = 0; at second 1 the depth raster is half the lake's size (s00.png,
s01.png)and at second 2, it completely disappears).

During the processing, I get the Courant-Friedrich-Lewy stability condition
warning message.

If I try to chose as computational method for initial velocity estimation,
uniform drop in of lake or small dam breach, I get the following error
"ERROR: Don't find the dambreak - Please select a correct map or adjust the
computational region".

Does anyone have an idea what could be the reason of these results, please?
Any suggestion would be highly appreciated.

Your water_depth should have 0 instead of nulls, I think that's the
problem in your case. The stability condition warning probably means
you should reduce your time step, on the other hand, it will take more
time.

Anna

Cheers,
Codrina

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grass-user mailing list
grass-user@lists.osgeo.org
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Cannata_Massimiliano · August 30, 2017, 8:56am

Hi, glad to see the module is used

If I correctly remember, you have to use a DEM with bathimetry and dam, then the dam break is passed trough a raster with decrements of dam height (it is use to calculate the new DEM after the dam breck by DEM - BREAK).

Best,
Maxi

···

2017-08-30 10:44 GMT+02:00 Codrina Maria Ilie <codrina@geo-spatial.org>:

Hi Anna,

You were perfectly right!
I changed from null to 0 and it works.

Thank you!
Codrina

On 29/08/2017 00:05, Anna Petrášová wrote:

Hi,

On Mon, Aug 28, 2017 at 4:53 PM, Codrina Maria Ilie
<codrina@geo-spatial.org> wrote:

Hi all,

I have been trying to run GRASS7 module r.damflood using the following
datasets:
[https://drive.google.com/drive/folders/0B2Yx_1shUSx3VThlY3BrV1JyWjg?usp=sharing],
with this command:

r.damflood --overwrite --verbose elev=dem lake=water_depth
dambreak=dam_breach manning=manning tstop=3 deltat=1 h=b_depth vel=b_vel
hmax=b_mwd vmax=b_mwv imax=b_mi wavefront=b_wf

To make it easier, the lake has a constant depth.

As far as I can understand, the rasters should be correctly built, but the
outputs of r.damflood are obviously wrong (rasters with nodata or one
category = 0; at second 1 the depth raster is half the lake’s size (s00.png,
s01.png)and at second 2, it completely disappears).

During the processing, I get the Courant-Friedrich-Lewy stability condition
warning message.

If I try to chose as computational method for initial velocity estimation,
uniform drop in of lake or small dam breach, I get the following error
“ERROR: Don’t find the dambreak - Please select a correct map or adjust the
computational region”.

Does anyone have an idea what could be the reason of these results, please?
Any suggestion would be highly appreciated.

Your water_depth should have 0 instead of nulls, I think that’s the
problem in your case. The stability condition warning probably means
you should reduce your time step, on the other hand, it will take more
time.

Anna

Cheers,
Codrina

grass-user mailing list
grass-user@lists.osgeo.org
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https://lists.osgeo.org/mailman/listinfo/grass-user

–

Massimiliano Cannata

Professore SUPSI in ingegneria Geomatica

Responsabile settore Geomatica

Istituto scienze della Terra

Dipartimento ambiente costruzione e design

Scuola universitaria professionale della Svizzera italiana

Campus Trevano, CH - 6952 Canobbio

Tel. +41 (0)58 666 62 14

Fax +41 (0)58 666 62 09

massimiliano.cannata@supsi.ch

www.supsi.ch/ist

Codrina_Maria_Ilie · August 30, 2017, 9:04am

Hi Moritz,

We had no real data for the lake bathymetry so we built it by artificially lowering the DEM values with a constant value. This is also the reason why the water depth is constant.

Regards,
Codrina

On 29/08/2017 00:29, Moritz Lennert wrote:

Le Mon, 28 Aug 2017 17:05:01 -0400,
Anna Petrášová <kratochanna@gmail.com> a écrit :

Hi,

On Mon, Aug 28, 2017 at 4:53 PM, Codrina Maria Ilie
<codrina@geo-spatial.org> wrote:

Hi all,

I have been trying to run GRASS7 module r.damflood using the
following datasets
[https://drive.google.com/drive/folders/0B2Yx_1shUSx3VThlY3BrV1JyWjg?usp=sharing],
with this command:

r.damflood --overwrite --verbose elev=dem lake=water_depth
dambreak=dam_breach manning=manning tstop=3 deltat=1 h=b_depth
vel=b_vel hmax=b_mwd vmax=b_mwv imax=b_mi wavefront=b_wf

To make it easier, the lake has a constant depth.

As far as I can understand, the rasters should be correctly built,
but the outputs of r.damflood are obviously wrong (rasters with
nodata or one category = 0; at second 1 the depth raster is half
the lake's size (s00.png, s01.png)and at second 2, it completely
disappears).

During the processing, I get the Courant-Friedrich-Lewy stability
condition warning message.

If I try to chose as computational method for initial velocity
estimation, uniform drop in of lake or small dam breach, I get the
following error "ERROR: Don't find the dambreak - Please select a
correct map or adjust the computational region".

Does anyone have an idea what could be the reason of these results,
please? Any suggestion would be highly appreciated.

Your water_depth should have 0 instead of nulls, I think that's the
problem in your case. The stability condition warning probably means
you should reduce your time step, on the other hand, it will take more
time.

r.null null=0 gets rid of the stability condition warning as well.

However, I don't know much about this module, but I'm a bit surprised
by your DEM: IIUC, it's level is lower in the entire dam lake area than
in the valley below. Also: is it normal that your water depth is
constant all over the lake ?

Moritz

Codrina_Maria_Ilie · August 30, 2017, 9:18am

Hi Maxi,

Yes, it is used and works well
You remember correctly, that was what I used.

Thank you and your colleague for the fine work at r.damflood.

Cheers,
Codrina

On 30/08/2017 11:56, Massimiliano Cannata wrote:

Hi, glad to see the module is used

If I correctly remember, you have to use a DEM with bathimetry and dam, then the dam break is passed trough a raster with decrements of dam height (it is use to calculate the new DEM after the dam breck by DEM - BREAK).

Best,
Maxi

2017-08-30 10:44 GMT+02:00 Codrina Maria Ilie <codrina@geo-spatial.org <mailto:codrina@geo-spatial.org>>:

    Hi Anna,

    You were perfectly right!
    I changed from null to 0 and it works.

    Thank you!
    Codrina

    On 29/08/2017 00:05, Anna Petrášová wrote:

        Hi,

        On Mon, Aug 28, 2017 at 4:53 PM, Codrina Maria Ilie
        <codrina@geo-spatial.org <mailto:codrina@geo-spatial.org>> wrote:

            Hi all,

            I have been trying to run GRASS7 module r.damflood using the
            following
            datasets:
            [https://drive.google.com/drive/folders/0B2Yx_1shUSx3VThlY3BrV1JyWjg?usp=sharing
            <https://drive.google.com/drive/folders/0B2Yx_1shUSx3VThlY3BrV1JyWjg?usp=sharing>\],
            with this command:

            r.damflood --overwrite --verbose elev=dem lake=water_depth
            dambreak=dam_breach manning=manning tstop=3 deltat=1
            h=b_depth vel=b_vel
            hmax=b_mwd vmax=b_mwv imax=b_mi wavefront=b_wf

            To make it easier, the lake has a constant depth.

            As far as I can understand, the rasters should be correctly
            built, but the
            outputs of r.damflood are obviously wrong (rasters with
            nodata or one
            category = 0; at second 1 the depth raster is half the
            lake's size (s00.png,
            s01.png)and at second 2, it completely disappears).

            During the processing, I get the Courant-Friedrich-Lewy
            stability condition
            warning message.

            If I try to chose as computational method for initial
            velocity estimation,
            uniform drop in of lake or small dam breach, I get the
            following error
            "ERROR: Don't find the dambreak - Please select a correct
            map or adjust the
            computational region".

            Does anyone have an idea what could be the reason of these
            results, please?
            Any suggestion would be highly appreciated.

        Your water_depth should have 0 instead of nulls, I think that's the
        problem in your case. The stability condition warning probably means
        you should reduce your time step, on the other hand, it will
        take more
        time.

        Anna

            Cheers,
            Codrina

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            grass-user mailing list
            grass-user@lists.osgeo.org <mailto:grass-user@lists.osgeo.org>
            https://lists.osgeo.org/mailman/listinfo/grass-user
            <https://lists.osgeo.org/mailman/listinfo/grass-user>

    _______________________________________________
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--
*Massimiliano Cannata*

Professore SUPSI in ingegneria Geomatica

Responsabile settore Geomatica

Istituto scienze della Terra

Dipartimento ambiente costruzione e design

Scuola universitaria professionale della Svizzera italiana

Campus Trevano, CH - 6952 Canobbio

Tel. +41 (0)58 666 62 14____

Fax +41 (0)58 666 62 09____

massimiliano.cannata@supsi.ch <mailto:massimiliano.cannata@supsi.ch>

_www.supsi.ch/ist <http://www.supsi.ch/ist>\_