[GRASS-user] r.damflood question

[Anna Petrášová]

Hi,

On Mon, Aug 28, 2017 at 4:53 PM, Codrina Maria Ilie
<codrina at 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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