[GRASSLIST:8619] Re: Interpolating and mapping the output of ecosystem models with GRASS

[Massimiliano Cannata]

Hi Luigi,
I'm currently working on something similar (hydrological model grass 
embedded) and I think the easiest way is to write some shell script 
doing what you need.
I think You should:
- read the file and generate a point feature (cat filename | v.in.ascii 
.....) maybe by using also awk for formatting your file...
- interpolate your points with one of the already existing modules 
(v.surf.rast, v.idw) and generate your raster
- then using map algebra (r.mapcalc) for set null the values of cell 
above your max height (r.mapcalc 
'final_map=if(dem>1500,interp_map,null())' )
I think it will be pretty easy to implement if you know some basis of 
shell programming....
Hope this could be useful.
Maxi


Luigi Ponti wrote:

> Dear GRASS Users Mailing List,
>
> I would like to ask some advice on using GRASS to map the output of 
> weather-driven population models for ecosystem analysis.
>
> Our group is considering GRASS as a way to map the georeferenced 
> output of the ecosystem models developed in our lab. In short, once 
> meteorological data (i.e., model input) and geographic data are 
> acquired for a particular landscape, an ecosystem model is run for 
> each weather station location of interest. Therefore, the output of 
> the model consists of a summary table combining the point locations of 
> the weather stations with the output value of interest.
>
> In order for this output to be mapped, an interpolation process is 
> needed to retrieve the spatial distribution of the values estimated by 
> the ecological model across the landscape. Another critical point is 
> the ability to 'clip' and eliminate areas which are not of interest to 
> the study, such as elevation which is too high, or other tracts of 
> land or water which are not of interest to the study.
>
> Would GRASS be able to interpolate such spatial distribution and also 
> 'clip' the out-of-interest areas? I am new to GRASS but I assume that 
> such capabilities are, at least potentially, already in place in 
> GRASS. What I cannot figure out is the amount of work needed to 
> implement such functionalities starting from the summary output table 
> that I mentioned above. Any hint is appreciated.
>
> Kind regards,
>
> Luigi Ponti
> Visiting Scholar
> University of California, Berkeley
> Environmental Science, Policy & Management
> lponti at nature.berkeley.edu
>
>
>


-- 

Eng. Massimiliano Cannata
Scuola Universitaria Professionale della Svizzera Italiana
Istituto Scienze della Terra
Via Trevano, c.p. 72
CH-6952 Canobbio-Lugano
Tel: +41 (0)58 666 62 18
Fax +41 (0)58 666 62 09