The ncgen utility can do the following with CDL input:

• Reverse what ncdump does, converting CDL to binary netCDF, for example:

      ncgen -o foo.nc foo.cdl
    

• Generate a C or Fortran program that, when compiled and run, will create a netCDF file corresponding to the CDL:

      ncgen -c foo.cdl > foo.c
    

  or

      ncgen -f foo.cdl > foo.f
    

Programming tip: if a program (e.g. a model) needs to create a netCDF file of specified structure, use a CDL file and ncgen to create the empty netCDF file with no data, then write the data using the appropriate "put_var" calls. For files with lots of metadata, this is easier than writing all the "boiler-plate" code to create the needed dimensions, attributes, and variables manually.

You can use ncdump and ncgen together for some simple netCDF editing:

• Use ncdump to convert netCDF file to CDL
• Use a text editor to change CDL (for example add, fix, or delete metadata or data)
• Use ncgen to turn modified CDL back into modified netCDF file
• This is not very practical for large netCDF files.

The Java tool toolsUI available with the netCDF Java package can similarly be used to convert back and forth between netCDF data and editable NcML.

NetCDF-4 note:  The current snapshot release of netCDF-4 includes an ncgen4 tool that handles features of the netCDF-4 data model in CDL. It can generate binary netCDF files or C, but not Fortran yet. To build it requires a non-default configure option, --enable-ncgen4 .

2008 Unidata NetCDF Workshop for Developers and Data Providers > NetCDF Utilities