[GRASSLIST:6207] Re: Water basin filling w Grass

[Māris Nartišs]

Hi,
tnx for idea about teraflow. I will try it. I'm newbie - so its hard
to find best tools for doing jobs :)

But second idea would not fit to my needs - I don't have any border
polylines for lakes - I need to find out possible lake locations,
maximum possible water levels and potential spill out points. All I
have is DTM and notes on some areas where possibly where lakes.

Yeah, I know it sounds crazy, but I have only some month to write
paper for my MSc ;)


Maris.

On Thu, 17 Mar 2005 17:19:38 +0100, Massimiliano Cannata
<massimiliano.cannata at supsi.ch> wrote:
>  For flat areas you can give a try to r.terraflow that manage this situation
> with a different approach.
>  For find the maximum heigth to have a spill maybe you have to find the
> lowest point around the border of the lake,
>  just an idea (probably stupid!): you can convert the border polyline to
> raster, with r.mapcalc get the heigth of the dem in the corrispondence cell
> and then with r.stats see the lower heigth in the map.
>  v.to.rast ....input=lake_border_polyline output=border
>  r.mapcalc 'dem_border=if(border,dem)'
>  r.stats dem_border
>  
>  Hello!
>  Max
> 
>  
>  
>  
>  Māris Nartišs wrote: 
>  Hi all, I'm doing research - a water body simulation with Grass. I
> successfully created DTM w Grass (Hooray!) and now need to do more specific
> things. I need to find maximum possible water level for lake. I have place
> where must be a lake and I need to know what water level is maximal until it
> starts to spill out. And I need to find those spill out points and levels
> (height). I know it is possible, because I saw a demo on web but w/o HOWTO.
> http://skagit.meas.ncsu.edu/%7Ehelena/gmslab/viz/erosion.html Any help,
> ideas welcome :) 
>
>And another question - I was following Grass tutorial (
> http://www.ing.unitn.it/~grass/docs/tutorial/english/index_en.htm ) and
> creating basins with r.watershed but on low land it produced thousands of
> small and narrow, parallel basins and result was not even close looking to
> sample shown on tutorial
> (http://www.ing.unitn.it/~grass/docs/tutorial/english/dtm4_en.htm). I
> understand, that different data give different results, but not so
> different! Or its OK and I was just confused by beautiful results shown in
> this tutorial? (See attachment.) Grass 6.0.0 b2 TNX for reading, Maris. 
>  
> -- 
>  _____________________________________________________ 
>  
>  Ing. Massimiliano Cannata 
>  
>  SUPSI - Istituto Scienze della Terra 
>  C.P. 72 - CH-6952 Canobbio (Ticino, Switzerland) 
>  Tel +41 (0)91 935 12 25 - Fax +41 (0)91 935 12 09 
>  mailto:massimiliano.cannata at supsi.ch 
>  http://www.ist.supsi.ch 
>  
>