[STATSGRASS] R-GRASS link problem

[Markus Neteler]

Hi,

just to note that these limitations no longer exist in recent GRASS 6.

Markus


Roger Bivand wrote:
> 
> On Wed, 8 Aug 2007, javier garcia-pintado wrote:
> 
>> Hi;
>> I've already reported this problem to the R list, but it is probable
>> that the source of the problem is GRASS (5.4) instead of R.
> 
> You wrote to R-help, not to R-sig-geo, which is the correct list on the R 
> side.
> 
>> I'm using the library GRASS in R to carry out a sequence of operation in
>> a set of GRASS maps.
>> After a couple of loops I obtain the warning message:
>> "Too many open raster files"
>> and the communication between R and GRASS does not work anymore for that
>> moment on.
>>
>> The fact is that I'm opening a sequence of maps, but the destination
>> name in R is always the same, so it does not seem to be an R problem but
>> a GRASS one.
>>
> 
> The GRASS package for legacy GRASS 5 has its own copy of the GRASS library 
> files that it calls, and the problem occurs when the number of "open" 
> files exceeds MAXFILES 256. You can change this in src/include/G.h and 
> re-build if you like, but since the C source of rastget shows you, it is 
> careful to close the file handles, line 214 in src/rastget.c. This leads 
> me to think that this is an OS story, and so we need to know your OS. 
> Here, Windows or cygwin may behave very differently when freeing system 
> resources from say Linux.
> 
> For me on Linux, running example(rast.get) outside GRASS (I do not have a 
> working GRASS 5 installation any more) and then running:
> 
> for (i in 1:260) {
>   print(i)
>   exget <- rast.get(G, rlist=c("ex.Zn.grid.in", "ex.tr3.in",
>    "ex.Zn.grid.o.in"), catlabels=as.logical(c(FALSE, FALSE, TRUE)))
> }
> 
> did not show any problems.
> 
> Roger
> 
>> Could you advise me about how to solve this?
>>
>> Thanks and best regards,
>>
>> Javier
>> ------------------------
>>
>>
> 
> -- 
> 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
> 

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