[R-sig-Geo] newbie question about R and GRASS

[Roger Bivand]

On Sun, 9 Jan 2011, Hodgess, Erin wrote:

> Dear R SIG Geo People:
>
> I'm trying to replicate the material on page 100 in Prof. Bivand ASDAR 
> book.  However, I am getting the following error message:
>
>
>> gmeta6()
> Error in if (file.exists(file) == FALSE) if (!missing(asText) && asText ==  :
>  argument is of length zero
> In addition: Warning message:
> running command 'g.region.exe --interface-description' had status 309
> Error in parseGRASS(cmd) : g.region not parsed
>>

No, this is not expected (checked with R 2.12.1 on Native GRASS 6.4.0 on 
Windows XP). You needed to provide full traceback() output, and 
sessionInfo(), and which Windows; verbatim output from loading spgrass6 
would also have been informative. Your problem is in your GRASS 
installation, as the message:

running command 'g.region.exe --interface-description' had status 309

shows.

Start GRASS 6.4.0 in MSYS mode, and try to run

g.region.exe --interface-description

from the console prompt. MSYS mode is helpful, because running R through 
the Layer Manager blocks the manager until R is terminated. Starting R in 
an existing location on Windows entails:

Starting GRASS in MSYS mode, choosing location and mapset as normal 
(Spearfish as location for the example refered to) - this sets many GRASS 
environment variables that are needed by spgrass6;

Starting R with the complete path, e.g.:

"C:/Program Files/R/R-2.12.1/bin/i386/Rgui.exe
R_LIBS=C:/Program Files/r_libs"

(line break for mailer)

in the MSYS console;

Check that spgrass6 reports the correct location on loading.

Hope this helps,

Roger

>
> This is in R-2.12.1 and GRASS version 6.4 on Windows.  Does this look 
> familiar, please?  Any suggestions would be much appreciated.
>
> Thanks,
> Erin
>
>
> Erin M. Hodgess, PhD
> Associate Professor
> Department of Computer and Mathematical Sciences
> University of Houston - Downtown
> mailto: hodgesse at uhd.edu
>
>
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>
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-- 
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