The Open Geospatial Consortium (OGC) membership has approved the Enhanced Data Model Extension to the OGC Network Common Data Form (netCDF) Core Encoding Standard. The Enhanced Data Model Extension, along with the Core Encoding Standard, the netCDF Binary Encoding Extension Standard – netCDF Classic, and the 64-bit Offset Format (adopted as official OGC standards in April 2011) are available for free download.
The enhanced data model (sometimes referred to as the netCDF-4 data model) is an extension to the classic model that adds new forms of data representation and new data types while preserving backward compatibility. Specifically, it adds six new primitive data types, four user-defined data types, multiple unlimited dimensions, and groups to organize data hierarchically and provide scopes for names.
Although it was originally developed for the Earth science community, netCDF can be used to communicate and store a wide variety of multidimensional data. The netCDF data model is particularly well suited to providing data in forms familiar to atmospheric and oceanic scientists, specifically, as sets of related arrays.
NetCDF is self-documenting, which means it can internally store information used to describe the data. For example, the internal documentation can associate various physical quantities (such as temperature, pressure, and humidity) with spatio-temporal locations (such as points at specific latitudes, longitudes, vertical levels, and times). Climate and Forecast (CF) Metadata Conventions are often used in conjunction with netCDF as a means of specifying semantic information that promotes the processing and sharing of climate and forecast data created with the netCDF application programming interface (API). The semantic metadata is conveyed internally within the netCDF datasets.
NetCDF was developed and is supported by the Unidata Program Center at the University Corporation for Atmospheric Research (UCAR) under sponsorship of the Atmospheric and Geoscience Division of the US Government National Science Foundation. It has been formally recognized by the US Government’s NASA and NOAA standards bodies. UCAR and other OGC members introduced netCDF into the OGC as a candidate OGC standard to encourage broader international use and greater interoperability among clients and servers interchanging data in binary form. Among other benefits, this will make the large collections of environmental netCDF data more readily accessible and usable by non-experts.
