[R-sig-Geo] memory limit...

[Edzer Pebesma]

Horacio Samaniego wrote:
> I'm trying to import a grass raster using
> 
> library(spgrass6)
> a = paste("prec",1:12,sep="")
> prec = readRAST6(a)
> 
> 
> this usually will create a SpatialGridDataFrame object width my 12
> grass rasters in the 'data' slot.
> 
> Howvere, I'm running intospace limitations in spite of having 8GB of
> Ram and large HD at the disposition of the CPU (2.9GHz Quad-Core)
> 
> I have tryed will little succed to star R with several flags to
> increase the memory. But I recognize to be lost in what part of the
> problem is due to the linux OS and which to R.

If the linux version is 64 bits, it will have no problem using all your
memory for a single process (R). Check it with:

$ uname -a
Linux ... 2.6.26-2-amd64 #1 SMP Thu Feb 11 00:59:32 UTC 2010 x86_64
GNU/Linux

the x86_64 here indicates it's a 64 bit platform. If you installed a 32
bit platform, processes are limited to 4 Gb, 3 Gb on a standard ubuntu
kernel, so you're lost, basically, until you reinstall linux.

> 
> Could anyone give me some guidelines on how to provide more memory to
> import raster maps under the sp model?

There is always the possibility that your maps are simply too large. How
large are they? Have you tried to import a single one? Two simple
thoughts: buy more RAM, or increase your swap space (and be patient).

Alternatives are to use package gdal, and not read the complete map in
memory but go through it tile by tile using [ to select, or use package
raster which is on r-forge.
-- 
Edzer Pebesma
Institute for Geoinformatics (ifgi), University of Münster
Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251
8333081, Fax: +49 251 8339763  http://ifgi.uni-muenster.de
http://www.52north.org/geostatistics      e.pebesma at wwu.de