NetCDF Status

Russ Rew and Ed Hartnett
September 13, 2005

NetCDF and Unidata

Work in maintaining, supporting, and developing the netCDF data model and software is associated with Endeavor 6: Improved scientific data access infrastructure from the Unidata 2008 proposal. NetCDF has become a key infrastructure element for producers and consumers of atmospheric science data, as well as data in other geosciences.

Recent netCDF development, both at Unidata and at other institutions, aims at generalizing the netCDF data model, improving interoperability with other representations for scientific data, making the netCDF interface more suitable for use on high-end parallel platforms with high-resolution models, and providing netCDF software on a wider range of desktop platforms.

NetCDF-4/HDF5 Development

In June 2005, Russ presented an overview of netCDF-4 and the Common Data Model to the GO-ESSP meeting at the British Atmospheric Data Centre.

Our partners in the NASA netCDF-4/HDF5 project, the HDF Group at NCSA, spun off a new independent non-profit corporation to continue maintenance, support, and development of HDF. For more information, see The HDF Group web site at

In August, we presented a review of the two-year netCDF/HDF project "Merging the NetCDF and HDF5 Libraries to Achieve Gains in Performance and Interoperability" to NASA staff and an independent reviewer. Materials resulting from the review, including the independent assessment of the project, are available from

Release of the netCDF-4 software is pending release of the new HDF5 enhancements it depends on, which will probably not be available to us until November at the earliest, with a public release early next year. There is considerable additional work to complete before the HDF5 release, including the Fortran-90 netCDF-4 interface and completion of new versions of netCDF utilities.

Other netCDF developments

Since the last status report, we made available a beta release of netCDF-3.6.1 to incorporate improvements to ease of installation, add a new interface for determining format version of an open file, and fix a bug involving large file support.

In April, we met with ESRI developers to discuss and resolve issues encountered while integrating netCDF support into ArcGIS.

Work continued on developing the Common Data Model and version 2.2 of the Netcdf-Java library that will implement it. With this software, it will be possible to access data in a number of other formats, including HDF5 and GRIB, through the same interface as for netCDF or OPeNDAP data.