[GRASSLIST:2060] Re: mapcalc for sites?

[Roger Bivand]

On Tue, 16 Dec 2003, Hamish wrote:

> 
> > Is there a way within GRASS to do calculations on sites?  I have some 
> > depth soundings that imports into float attributes to my sites and
> > need to convert them to elevations (and to meters) before I run one of
> > the surf commands.  I would rather not go outside of GRASS to do it
> > (too much import/export hassle), but I have the tools if necessary.
> 
> Probably best to do it externally.
>  
>  s.out.ascii sites_file -ad fs=, > site_data.dat
> 
> 
> Then
> 
> if the number of soundings is small:
> load into a spreadsheet and make the changes you need.
> 
> if the number of soundings is large:
> load into something like Octave or Matlab & do your thing.
> 
> 
> Save in a similar CSV format & re-import with s.in.ascii. Mind the
> spreadsheet hasn't rounded your data on a whim as some of them are want
> to do.
> 
> 
> Within GRASS, you can only do stats on the site data, not actually
> change them, AFAIK.
> 

An alternative if you use R and the R/GRASS interface is sites.get() to R, 
do the computations, then sites.put2() back again. But for smaller 
operations, use the other suggestions to save installing extra software.

Roger

> 
> good luck,
> Hamish
> 
> 

-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Breiviksveien 40, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93
e-mail: Roger.Bivand at nhh.no