R help - Feb 2008 - Plan to build Package to use GRASS from R

Hi

Sorry for crossposting, but I think this can be of interest for GRASS and R
users.

I am planning to write a package to make the use of GRASS from R easier. The
idea is to wrap the system call to execute the GRASS command into an R
command of the same name.
e.g:
r.to.vect <- function(..., intern=TRUE, ignore.stderr=FALSE)
  {
    comm <- paste( "r.to.vect ", ..., sep="" )
    print(comm)
    system( comm, intern=intern, ignore.stderr=ignore.stderr )
  }

My questions are:

1) Is this a good way of doing it, or is giving a named list to the function
more usefull?
2) Is there a way to obtain easily all commands from GRASS and the
parameters possible and required?

Any ideas and comments welcome,

Rainer


-- 
Rainer M. Krug, Dipl. Phys. (Germany), MSc Conservation Biology (UCT)

Plant Conservation Unit Department of Botany
University of Cape Town
Rondebosch 7701
South Africa

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On 27/02/2008, Virgilio Gomez-Rubio <v.gomezrubio@imperial.ac.uk>
wrote:
>
> Hi,
>
> >
> > if you are refering to spgrass6, yes, But if I want to execute
> > commands in GRASS, I still have to use system(...)
>
>
> OK. I just wanted to check... :) Not sure what ROger Bivand will think,
> but maybe it would be better to add waht you develop to that package.

Sounds like a perfect suggestion - otherwise everything could become to
fragmented and difficult to use.


Regards,
>
>
> Virgilio
>
>
>

-- 

-- 
Rainer M. Krug, Dipl. Phys. (Germany), MSc Conservation Biology (UCT)

Plant Conservation Unit Department of Botany
University of Cape Town
Rondebosch 7701
South Africa

	[[alternative HTML version deleted]]

On Wed, 27 Feb 2008, Rainer M Krug wrote:
> Hi
>
> Sorry for crossposting, but I think this can be of interest for GRASS and R
> users.
Yes, please avoid cross-posting - the discussion ends up on many different 
lists and threading can break down if the threading implementation in mail 
clients and archives doesn't like cross-posting.

The only complete thread I have found is on Nabble at:

http://www.nabble.com/Plan-to-build-Package-to-use-GRASS-from-R-tt15712877.html#a15712877

for the grass-dev list.

In summary, the problems are mostly those of appropriately quoting shell 
commands through system() across platforms. Those interested should follow 
the discussion on grass-dev.

The correct lists could be either here, or the grass-stats list; could 
Rainer post a summary to both (hopefully in-thread) on conclusion?

Roger
>
> I am planning to write a package to make the use of GRASS from R easier.
The
> idea is to wrap the system call to execute the GRASS command into an R
> command of the same name.
> e.g:
> r.to.vect <- function(..., intern=TRUE, ignore.stderr=FALSE)
>  {
>    comm <- paste( "r.to.vect ", ..., sep="" )
>    print(comm)
>    system( comm, intern=intern, ignore.stderr=ignore.stderr )
>  }
>
> My questions are:
>
> 1) Is this a good way of doing it, or is giving a named list to the
function
> more usefull?
> 2) Is there a way to obtain easily all commands from GRASS and the
> parameters possible and required?
>
> Any ideas and comments welcome,
>
> Rainer
>
>
>
-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no