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The Climate and Forecast (CF) [[metadata]] conventions are conventions for the description of [[Earth sciences]] data, intended to promote the processing and sharing of [[data file]]s. The metadata defined by the CF conventions are generally included in the same file as the data, thus making the file "self-describing". The conventions provide a definitive description of what the data values found in each [[netCDF]] variable represent, and of the spatial and temporal properties of the data, including information about grids, such as [[grid cell]] bounds and cell averaging methods. This enables users of files from different sources to decide which variables are comparable, and is a basis for building software applications with powerful [[data extraction]], grid remapping, [[data analysis]], and [[data visualization]] capabilities.
==History and evolution==
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* Redundancy should be avoided to prevent inconsistencies when writing data.
Specific CF metadata descriptors use values of attributes to represent
* [[Data provenance]]: <code>title</code>, <code>institution</code>, <code>contact</code>, <code>source</code> (e.g. model), <code>history</code> ([[audit trail]] of operations), <code>references</code>, <code>comment</code>
* Description of associated activity: <code>project</code>, <code>experiment</code>
* Description of data: <code>units</code>, <code>standard_name</code>, <code>long_name</code>, <code>auxiliary_variables</code>, <code>missing_value</code>, <code>valid_range</code>, <code>flag_values</code>, <code>flag_meanings</code>
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* Meaning of grid cells: <code>cell_methods</code>, <code>cell_measures</code>, and climatological statistics.
A central element of the CF Conventions is the CF Standard Name Table. The CF Standard Name Table uniquely associates a standard name with each geophysical parameter in a [[data set]], where each name provides a precise description of physical quantities being represented. Note that this is the string value of the <code>standard_name</code> attribute, not the name of the parameter. The CF standard name table identifies over 1,000 physical quantities, each with a precise description and associated [[canonical units]]. Guidelines for construction of CF standard names are documented on the conventions web site.
As an example of the information provided by CF standard names, the entry for sea-level atmospheric pressure includes:
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==Software==
*[https://ncas-cms.github.io/cf-python/ CF-Python] is a data analysis package built on a complete implementation ([https://ncas-cms.github.io/cfdm/ CFDM]) of the CF conventions. The authors of the CFDM and CF-Python currently assert a desire to fully support all aspects of the CF conventions.
*[
* [[Origin (data analysis software)|OriginPro]] version 2021b supports<ref> {{cite web|url=https://www.originlab.com/doc/Origin-Help/NetCDF-Importing-Processing| title=NetCDF Importing and Processing |publisher=originlab.com |access-date=2021-05-11}}</ref> netCDF CF Convention. Averaging can be performed during import to allow handling of large datasets in a GUI software.
* The [https://xarray.pydata.org xarray] Python library parses and decodes data stored according to CF Conventions.
* The [https://scitools-iris.readthedocs.io/en/stable/index.html Iris] Python library "draws heavily from the NetCDF CF Metadata Conventions as a source for its data model".<ref> {{cite web| url=https://scitools-iris.readthedocs.io/en/stable/further_topics/metadata.html| title=Metadata - Iris Documentation| access-date=2023-02-10}}</ref>
==References==
{{Reflist}}
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