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Service Parameters (Service Keywords)


The <Service_Parameters> field allows for the specification of Earth science services keywords that are representative of the services, tools, and/or resources being described. These keywords are important for the precise search and retrieval of information from the GCMD. The author must select these keywords from the controlled set of services keywords. The <Service_Parameters> field consists of a 4-level hierarchical classification of services keywords, defined as follows:

  • <Service_Category> is the highest keyword category. The default is "EARTH SCIENCE SERVICES".
  • <Service_Topic> is the next highest level in the keyword hierarchy under <Category>. There are 8 Topics:
    • Data Analysis and Visualization
    • Data Management/Data Handling
    • Education/Outreach
    • Environmental Advisories
    • Hazards Management
    • Metadata Handling
    • Models
    • Reference and Information Services
    • Web Services
  • <Service_Term> is next level in the hierarchy under <Service_Topic>. There can be several controlled <Service_Term> keywords for each <Service_Topic>.
  • <Service_Variable> is the next level in the hierarchy under <Service_Term>.There can be several controlled <Service_Specific_Name> keywords for each <Service_Term>.

<Service_Category>EARTH SCIENCE SERVICES</Service_Category> (by default)
<Service_Topic>Topic keyword</Service_Topic>
<Service_Term>Term keyword</Service_Term>
<Service_Variable>Variable keyword</Service_Variable>

  • <Service_Category>, <Service_Topic>, <Service_Term>, and <Service_Specific_Name>, must be selected from the set of controlled Earth science services keywords.
  • The <Service_Parameters> field is required field and repeatable.
  • The following fields within <Service_Parameters> are required and may not be repeated within the <Service_Parameters> field:
    • <Service_Category>
    • <Service_Topic>
    • <Service_Term>
  • The <Service_Specific_Name> field within <Service_Parameters> is optional and may not be repeated

Multiple <Service_Parameters> can be specified for each metadata record. All applicable <Service_Topic>, <Service_Term>, and <Service_Specific_Name> services keywords should be selected that describe the service.

Specification of <Service_Parameters> without a  <Service_Specific_Name> keyword.

<Service_Category>Earth Science Services</Service_Category>
<Service_Topic>Data Management/Data Handling</Service_Topic>
<Service_Term>Data Search and Retrieval</Service_Term>

Specification of <Service_Parameters> with a <Service_Specific_Name> keyword.

<Service_Category>Earth Science Services</Service_Category>
<Service_Topic>Environmental Advisories</Service_Topic>
<Service_Term>Space Weather Advisories</Service_Term>
<Service_Specific_Name>Aurora Forecasts</Service_Specific_Name>


This document should be cited as:
Service Entry Resource Format (SERF) Writer's Guide, 2018.
Global Change Master Directory.
National Aeronautics and Space Administration.



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