The netCDF-4 data model is also known as the Unidata Common Data Model, because of an ongoing effort to identify a common subset of netCDF, HDF5, and OPeNDAP data models to improve interoperability for data providers and users.
The UML representation of the netCDF-4 data model below highlights in red the additions to the netCDF-3 data model, showing netCDF-4 is a fairly simple extension of netCDF-3.
More details about netCDF-4 will be covered in a subsequent section.