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Re: 960604: Installation Problems

>Organization: National Weather Service
>Keywords: 199606042048.AA09955

Hi Glen,

>       I currently have the following two netCDF files and cdl file which
>      I am trying to convert from netCDF:
> 
>                        961361500q.cdf
>                        latest_q.cdf
>                        acars.cdl

I don't recognize those file names as something produced by any of our
packages, but the ".cdl" extension is used for ASCII text files that
provide a human-readable and human-editable version of a binary netCDF
file, or just the structure of the netCDF file (dimension names and sizes,
variable names types and shapes, etc.) without any data.  We use and
recommend the use of ".nc" as a file name extension for netCDF files rather
than ".cdf", because the latter can be confused with NASA's CDF format
files.  I'll assume these files are really netCDF rather than CDF, and that
they were generated by a decoder or application that I don't know about.

>       I have gotten the software from unidata via ftp and uncompressed
>      the file to expand into its series of directories.  Currently, I am
>      trying to get an understanding of how to begin using this software
>      to read the files specified above.  Would you know what I need to
>      do next or persons I may need to get in contact with to insure that
>      I am going about this process correctly.
> 
>       After performing a "configure" and "make all", I tried using the
>      command "ncdump 961361500q.cdf".  This resulted in a segmentation
>      fault core dump.

Since you didn't do a "make install" to put the ncdump program that you
just built in a directory where it would be found, are you sure you're
actually using the ncdump program you just built?  After "make all", the
ncdump program would have just been left in the netcdf/src/ncdump/
directory, where you would have had to explicitly invoke it, if you hadn't
included that directory in your executable search path.  You can install
ncdump in your own bin/ directory if you just want to use it for browsing
netCDF files without installing it for general use.

To see if the ncdump you are using is the one you just built, try invoking
"which ncdump".

If you are getting a segmentation fault from a current version of ncdump,
that's a bug that we'd like to know more about.  If that's the case, please
verify that you are using version 2.4.2 of netCDF software (from the
VERSION file in the top-level netcdf src/ directory), and tell me what
platform (machine and operating system version) you built it on, and which
compiler you used, if it was not the standard vendor-supplied compiler
(this information is available in the output of running the "configure"
script).

We'd also like to know if the 961361500q.cdf file you are using is really a
netCDF file (though if it wasn't, ncdump should immediately report "not a
netCDF file" and exit rather than getting a segmentation fault).  You can
tell this by looking at the first line of output from "od -c 961361500q.cdf",
which should look something like:

    0000000   C   D   F 001  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0

where the first four bytes should be displayed as "C", "D", "F", and "001".

______________________________________________________________________________

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