NetCDF

NetCDF is a scientific file format for array-based data. The latest technical developments were summarized for the netCDF workshop Aug 2009 by Unidata (ppt).

It has the following pros:

• Any amount of meta-data (Attributes) can be appended.
• It can handle large datasets (file size > 4GB allowed with in 64-bit offset mode).
  • It is fully scaleable for future applications.
• It is open source.
• It is simple yet robust.

  Following examination by 20 reviewers, NASA's Earth Science Data Systems Standards Process Group has concluded that netCDF classic should be adopted as a recommended standard.

  A major strength of netCDF classic, according to the reviewers, was that it has fostered data interoperability and exchange through its self-describing file format, platform independent architecture, and robust access methods. Additionally, its overall file format and metadata attributes were simple enough to be easily understood and applied yet robust enough to describe and store multidimensional data of different types in the same file (source: Unidata news)

• netCDF data storage and retrieval is very fast (direct access binary).
• netCDF data storage is small due to its storage efficiency (binary is small, and it can be zipped internally too).
• There are two independent open source implementations of the NetCDF interface (C & Java).
  • reliable
  • redundant
• It is generally used, so there are always someone who can can offer help available.
• netCDF is the de facto standard for coastal ocean circulation models (GOTM, ROMS, ECOM-SED and in the near future also Delft3D-FLOW).
• There are lots of simple tools out there on the web that operate on NetCDF files (list):
  • ncBrowse (recommended!)
  • ToolsUI
  • Panoply
  • ncview (linux)
  • NCO (command line)
  • ncview (linux)
  • Delft3D-QuickPlot (licensed)
• There are lots of interfaces to sophisticated scientific data manipulation languages (list):
  • Matlab
    • mexcdf interface on C-interface (code) .
    • mexcdf interface on java-interface (code) .
    • Netcdf-Java Toolbox for Matlab (njTBX) on java-interface.
    • native matlab interface (since release 2008b)
  • Python
  • IDL
• The latest netCDF interfaces contain the OPeNDAP-interface, which allows you to handle an *.nc file on the web as if it were on your PC.
• There are additional, widely accepted conventions for NetCDF that are implemented in the main NetCDF viewers. Following Unidata, the maker of netCDF, we very stringly recommend to adhere to:
  • CF meta data convenction. See also: Best practices for writing netCDF files.