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GCMD Keyword Requirements

A set of controlled keyword requirements (below) are a criteria used when determining what constitutes a well-curated keyword list.

  • Keywords should be applicable to an established science discipline and practical to a broad range of users and metadata providers.
  • Keywords should be composed of conventional terminology that is functional and understandable by the international community.
  • Keywords should not overlap with keywords that already exist.
  • Keywords that are frequently searched for in free-text searches, but that are not already part of the existing keywords are often good candidates for new keywords.
  • Keywords that are commonly populated in the uncontrolled Detailed Variables field will be considered for inclusion into the controlled GCMD keywords.
  • Keywords should only be considered if applicable to existing or forthcoming Earth science data/metadata (e.g. a new project, instrument, mission, or collaboration).
  • Keywords must be parallel in scope at any level of the hierarchy.
    • Example: a broad and narrow keyword should not be included within any one level of the hierarchy.
  • All chosen topics, terms, and variables, at any level within the hierarchy, must be distinctive - minimizing overlap as much as possible. This will ensure a concise keyword list.
  • Keywords in the hierarchy should be logically/semantically correct.


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