Re: Apparent filesize limit?

John,

My guess is that you have run into one of the Netcdf 3 limitations. There is a way to have *one* single variable larger than 2^31 bytes, but you must do several things properly. Please read the details here and check that you are following all of the rules:

http://www.unidata.ucar.edu/software/netcdf/docs/netcdf/NetCDF-Classic-Format-Limitations.html

For data in excess of one gig, I recommend that the data remain in multiple files, and that some simple scheme be used to read in the file set at the start of application programs.

One such scheme which is common, sometimes called "templating", uses a consistent part of the filename to span multiple files. E.g. data.1990.nc, data.1991.nc, etc. So a one line "open" statement becomes a loop that's a few lines long, and filenames are constructed on the fly. HTH.

--Dave A.
CIRES Climate Diagnostics Center (CDC)
NOAA/ESRL, Physical Sciences Division (PSD)

Thaden, John J wrote:
Hello, I've created a NetCDF convention to amass into one outputfile results contained in many (e.g. 50) NetCDF files (of the AnDI for spectrometry type). Data in the new convention include two 3-D arrays, with their unlimited dimension being the number of input files. But these conventions/types may be unimportant to my question.

After some coding false starts, I can now iterative through
a list of input files and load data into the output file
without obvious memory problems. But all stops at iteration 38, when the output file just exceeds 2 gigabytes, specifically, when it is 2,097,144 kilobytes. My question: Have I run up against a NetCDF file size Limitation? Or is this some glitch in R or in Windows?

Thanks,
-John

P.S. I'm working in the R (v. 2.3.1) statistical programming environment. I use Pavel Michna's RNetCDF (v.1.2-1) package within R to access netcdf (v. 3) library functions. This is all happening on a Windows XP laptop with 512 M RAM. The command in my iteration that fails is "var.put.nc". The error is generated from a line "stop(nc$errmsg, call. = FALSE). The error
message is "Invalid Argument".  -JT

John Thaden PhD
University of Arkansas for Medical Sciences
Little Rock AR, USA

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