problems with memory limits of R

Dear everybody,

can anybody help me?

I was trying to import raster maps on R of more than 20 MB size and I 
got memory size limit problem. I found on R-help that probably I would 
have to work with a 64 bit R version. But to use a 64 bit version of R I 
think that I should need a 64 bit version of windows, isn't it?

Maybe I'm not looking the right solution to this problem and I really 
don't now how to go on!

Please follow the posting guide carefully. Please always state the output 
of sessionInfo(). The latest version of sp may help, but we do not know 
which version of R, sp, rgdal?, maptools?, whatever, you are using. All we 
know is that you are using Windows, for which no 64-bit version of R is 
currently available, and where Windows is known to have worse memory 
management, because it has more difficulties arranging smaller fragmented 
free memory chunks into a larger requested allocation.

Do you need to load 20MB rasters (this is a very imprecise description - a 
20MB geotiff may be very large indeed after compression is removed), even 
if 20MB means 20M raster cells (say 5000 by 4000, multiplied by 8 for 
double precision per band)? Can you use subsetting in rgdal to read tiles 
of data? Please also review the R for Windows FAQ on memory constraints - 
Q2.9.

Roger

bye, Maria Fantappi?

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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