A netCDF file has a path name and possibly some dimensions, variables, global (file-level) attributes, and data values associated with the variables. Sometimes we refer to netCDF files more abstractly as datasets.

In the enhanced data model, files may contain one or more groups, with each group functioning as a classic model dataset. In the enhanced data model, groups may be nested.

Operations supported on netCDF files include:

• Create a new file, given its path name and whether to overwrite or not.
• Open an existing file for access, given dataset name and read or write intent.
• Put into define mode to add dimensions, variables, or attributes.
• Take out of define mode, checking consistency of additions.
• Close, writing to disk if required.
• Get the number of dimensions.
• Get the number of variables.
• Get the number of global attributes.
• Get the unlimited dimension, if any.
• Synchronize to disk to make sure file matches memory.
• Set and unset no fill mode for optimized sequential writes.

2010 Unidata NetCDF Workshop > The Two NetCDF Data Models