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  • \section{Conversion to NetCDF files}
    
    \subsection{{\tt lfi2cdf} tool}
    
    The \texttt{lfi2cdf} tool converts the binary part (or LFI file) of a
    FM file (synchronous or diachronic) into a NetCDF file.  All the fields
    (or more precisely all the LFI articles) contained in the input LFI file
    are copied to the NetCDF output file with their values unchanged. As
    a LFI article does not hold any information on the variable, the tool
    tries to describe the corresponding NetCDF variable by using~:
    
    \begin{itemize}
    \item 3 LFI articles: \texttt{IMAX, JMAX,} and \texttt{KMAX}
      if they are available in the LFI input file. These articles may
      provide the NetCDF dimensions \texttt{DIMX, DIMY,} and \texttt{DIMZ}
      of an array variable. If these variables are not available in the
      input file, the tool treats each array variable as a 1D array.
    \item a small database implemented as a structure array in the
      \texttt{lfi2cdf} source file \texttt{fieldtype.f90}. This array
      holds the type (\texttt{REAL, INTEGER, LOGICAL}\ldots) of every
      common LFI article. When an article is not present in this database,
      its name is displayed on \texttt{stdout} by the running tool, and
      the corresponding values are always considered as \texttt{REAL}
      values. A new LFI article type description can be easily added in
      the \texttt{fieldtype.f90} source file and the tool must be then
      recompiled.
    \end{itemize}
    
    \subsubsection{Usage}
    The binary part of the FM file is required in the current directory.
    The following commands convert a file \texttt{myfile.lfi} from LFI to NetCDF:
    
    \begin{verbatim}
    lfi2cdf myfile.lfi
    \end{verbatim} 
    or
    \begin{verbatim}
    lfi2cdf myfile
    \end{verbatim}
    
    \noindent The output NetCDF file is named:
    \texttt{myfile.cdf}. 
    %myfile{\bf .cdf}. 
    It can easily be manipulated by NetCDF tools\footnote{see
    freely available NetCDF software at  http://www.unidata.ucar.edu/packages/netcdf/software.html} like
    \texttt{ncdump}, \texttt{ncview}, or \texttt{NCO} operators.\\
    
    \noindent In the same way, you will convert a NetCDF
    file \texttt{myfile.cdf} back to LFI format by typing:
    
    \begin{verbatim}
    cdf2lfi myfile.cdf
    \end{verbatim}
    or
    \begin{verbatim}
    cdf2lfi myfile
    \end{verbatim}
    The output LFI file is then named: \texttt{myfile.lfi}
    
    
    \subsection{{\tt extractdia} tool}
    The \texttt{extractdia} tool converts a diachronic FM file into a NetCDF file after an extraction of a list of fields and an optional extraction of a sub-domain.  See the section \ref{extractdia}.
    
    
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