[GRASS-user] Problem in running r.sim.water

[vishal tiwari]

Dear Ma'am,

Thank you for your response. Over the past couple of days I tried the
r.sim.water over various number of data-sets and I was able to get the
results for elevation data which have resolution of size greater than 10m.
Although the results for very high resolution data-set were not getting
generated even though the dimensions of the grid was not too big.

So I created two kind of data-sets each having the following meta data:

First (Not working) =>

 |   Type of Map:  raster               Number of Categories:
255             |
 |   Data Type:
FCELL                                                      |
 |   Rows:
49                                                         |
 |   Columns:
131                                                        |
 |   Total Cells:
6419                                                       |
 |        Projection: UTM (zone
13)                                           |
 |            N: 52.33036335    S: 52.32309305   Res:
0.00014837              |
 |            E: 13.04243697    W: 13.03048443   Res:
0.00009124              |
 |   Range of data:    min = 43  max = 103

Second (working) =>

 |   Type of Map:  raster               Number of Categories:
255             |
 |   Data Type:
FCELL                                                      |
 |   Rows:
53                                                         |
 |   Columns:
140                                                        |
 |   Total Cells:
7420                                                       |
 |        Projection: UTM (zone
13)                                           |
 |            N: 52.33058068    S: -477.66941932   Res:
10                 |
 |            E: 1413.03011844    W: 13.03011844   Res:
10                 |
 |   Range of data:    min = 43  max =
103                                    |
 |
|

First (original) and second both are the same data-set. Second is generated
by changing the resolution size to 10 (in degress, thus changing the S and
E coordinates, which are wrong). But the original data-set have the pixel
size of 10m X 10m (but shown in degrees).

My question being does the format of the datasets projection have to be in
a specific projection format for r.sim.water to work?

Also can you please help me figure out how are the "Time step" value and
"Number of iterations" in the simulation are being calculated, by pointing
me to some references?

Also apologies for the late relay.

Thank you and kind regards,
Vishal Tiwari

On 13 June 2015 at 16:38, Markus Neteler <neteler at osgeo.org> wrote:

> On Wed, Jun 10, 2015 at 11:21 AM, vishal tiwari <hi.vishal123 at gmail.com>
> wrote:
>
>> Hi all,
>>
>> I am trying to run the r.sim.water in GRASS. I have calculated the
>> partial derivatives dx and dy rater map using r.slope.aspect. I am using
>> this elevation map [1] to get the time-series depth map. But I think the
>> output file is not being saved in the "outputDepth" rater map (says failed
>> to open, on seeing the metadata).
>>
>> > r.sim.water -t elevin=testElevationLive at sampleMapSet
>> dxin=dx at sampleMapSet dyin=dy at sampleMapSet rain_val=150 manin_val=0.015
>> depth=outputDepth nwalk=50000 outiter=20
>>
>> STDOUT:
>>
>> Min elevation   = 43.00 m
>> Max elevation   = 103.00 m
>> Mean Source Rate (rainf. excess or sediment)    = 0.000030 m/s or kg/m2s
>> Mean flow velocity  = 21.486384 m/s
>> Mean Mannings   = 0.015121
>> Number of iterations    = 647482826 cells
>> Time step   = 0.00 s
>>
>> and on the command console:
>>
>> Command 'd.rast map=outputDepth at sampleMapSet' failed
>> Details: Raster map <outputDepth at sampleMapSet> not found
>>
>> [1] https://www.dropbox.com/s/ooxcj0y6v2kzeml/testElevationLive.tif?dl=0
>>
>> Thanks and Regards,
>>
>
>
> For the list archive record, the offlist answer by Helena Mitasova:
>
> On Fri, Jun 12, 2015 at 10:52 PM, Helena Mitasova wrote:
> > It is possible that there is no output - with time step smaller than
> 0.001 it looks like you are running it at very high resolution
> > on a huge DEM for some extreme storm event (150mm/hour - is that what
> you are trying to model?)
> > or you just don’t have your region set properly. To test, try to
> increase the grid cell size and use 50mm/hr storm.
> >
> > Helena
> >
>
>
> Markus
>



-- 
Vishal Tiwari
Computer Science and Engineering
Lab for Spatial Informatics
IIIT-Hyderabad
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