Unidata's Common Data Model (CDM) is an abstract data model for scientific datasets. It merges the netCDF, OPeNDAP, and HDF5 data models to create a common API for many types of scientific data.
The NetCDF Java library is an implementation of the CDM which can read many file formats besides netCDF.
The Common Data Model has three layers, which build on top of each other to add successively richer semantics:
- The data access layer, also know as the syntactic layer, handles data reading and writing.
- The coordinate system layer identifies the coordinates of the data arrays. Coordinates are a completely general concept for scientific data; we also identify specialized georeferencing coordinate systems, which are important to the Earth Science community.
- The scientific feature type layer identifies specific types of data, such as grids, radial, and point data, adding specialized methods for each kind of data.