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[netCDF #DON-496465]: netcdf help

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  • Subject: [netCDF #DON-496465]: netcdf help
  • Date: Wed, 23 Feb 2011 16:20:45 -0700
Hi Morgan,

> I'm a graduate student at MIT and I've just started working with some very
> large hurricane model output data. I found your email on the Unidata website
> and thought you might be able to help me.
> 
> I have a number of compressed output files that I can convert to netcdf
> using a pgf90 (*pgf90 filename.f -o filename -Mbyteswapio -I${INC_NETCDF}
> -L${LIB_NETCDF} -lnetcdf*). Each file is a little larger than 2GB, and the
> final variable I need is not retained in the subsequent netcdf file. From
> what I've just read, it seems as though the 64-bit LFS would let the netcdf
> file hold all of the variables. What option should I add to the conversion
> (copied above) to switch the format?

If you're asking about writing netCDF-3 files that make use of LFS to
support 64-bit file offsets, you have to provide a flag to the
nf_create() (or nf90_create()) function to indicate your use of that
variant of the "netCDF-3 classic" format, e.g. see the answer to this
FAQ:

  How do I create a 64-bit offset netCDF file from C, Fortran-77, Fortran-90, 
or C++?
  
http://www.unidata.ucar.edu/software/netcdf/docs/faq.html#Large%20File%20Support8
 
Even with the 64-bit offset netCDF-3 file format, there are some
limitations on variable sizes:

   
http://www.unidata.ucar.edu/software/netcdf/docs/faq.html#Large%20File%20Support10

There are other answers in that section of the FAQ 

   
http://www.unidata.ucar.edu/software/netcdf/docs/faq.html#Large%20File%20Support

that may help if I've misunderstood your question.  Otherwise, we'll
need more specifics about your converion program.

--Russ

Russ Rew                                         UCAR Unidata Program
address@hidden                      http://www.unidata.ucar.edu



Ticket Details
===================
Ticket ID: DON-496465
Department: Support netCDF
Priority: Normal
Status: Closed