Page tree
Skip to end of metadata
Go to start of metadata

Click Here to Return to the GCMD Keywords Community Forum Home

Click Here to Return to the GCMD Keyword Landing Page

What Are the GCMD Keywords?

The GCMD Keywords are a hierarchical set of controlled Earth Science vocabularies that help ensure Earth science data and services are described in a consistent and comprehensive manner and allow for the precise searching of collection-level metadata and subsequent retrieval of data and services. Initiated over twenty years ago, the GCMD Keywords continue to be refined and expanded in response to user needs. The sets of GCMD Keywords are as follows.

  • Earth Science Keywords                                                                 
  • Earth Science Services Keywords            
  • Data Centers                                             
  • Projects                                                     
  • Instrument/Sensors
  • Platforms/Sources                    
  • Locations
  • Horizontal Data Resolution
  • Vertical Data Resolution
  • Temporal Data Resolution
  • URL Content Types
  • Chronostratigraphic Units

How Do I Submit a Keyword Request or Issue?


To submit a keyword request (addition or modification) the submitter should:

  1. State the proposed keyword
  2. Provide a definition of the keyword
  3. State the rationale for the keyword addition or modification
  4. Review the keyword rules (criteria used when determining what constitutes a well-curated keyword list)

  5. Verify that the keyword does not already exists by checking the keywords in the Keyword Directory and search for the keyword

Once the above steps have been completed, submit the request to or post to the forum.The submitter will be notified of their submission status and when the keyword change has been made.

Other keyword issues/questions should be posted to the keyword forum.

How Long Will It Take for My Keyword To Be Reviewed?


Fast-Track Keywords:

  • An expedited review process (less than five business days) for proposed additions and changes that are small and have little or no impact on other users and metadata providers.

Full-Review Keywords

  • The full review process for proposed GCMD keyword changes is a review process facilitated by the ESDIS Standards Office (ESO) with input from subject matter experts drawn from the user and provider communities. These reviews take longer (1-2 keyword releases a year) to complete and are used for GCMD keyword changes or changes that have a large impact on existing users.

The keyword submitter will be notified whether their keyword is considered a fast-track or full review.

How Do I Cite the GCMD Keywords?

The GCMD Keywords should be cited as:

Global Change Master Directory (GCMD). 2018. GCMD Keywords, Version 8.6. Greenbelt, MD: Global Change Data Center, Science and Exploration Directorate, Goddard Space Flight Center (GSFC) National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page):



  • No labels