What is a SERF?
SERF is the acronym for Service Entry Resource Format, a de-facto standard used to create directory entries that describe a group of data services and applications. A SERF consists of a collection of fields that detail specific information about the service. Seven fields are required in the SERF; the others expand upon and clarify the information. Some of the fields are free text or unrestricted fields, others require the use of valid values.

The SERF allows users of data to find tools to manipulate data. The SERF contains those fields that are necessary for users to decide whether a particular service would be useful for their needs.

The Global Change Master Directory (GCMD) offers online descriptive information about environmental and Earth science data sets located throughout the world. As an additional service for the Earth sciences community, GCMD also offers descriptive information about commercial and non-commercial data services that could assist its user community in analyzing, processing, and evaluating Earth science data sets.

Parameter Keyword Rules

by Lola M. Olsen

The following rules have been used in determining TERMs and VARIABLEs for the GCMD Parameter Keywords. These rules are used in GCMD's procedures for modifying GCMD keywords. TOPICs, TERMs, and VARIABLEs contain VALID lists to assist the user in locating Earth science data sets of interest. These VALIDs are expected to remain fairly stable over time, although suggestions for additions and/or changes will always be considered.

 

RULES

    1) The service advertised in the GCMD must be specific and directly related to the processing, viewing, analysis, archival, retrieval, production, interpretation, acquisition, modeling, visualizing, formatting, or indexing of Earth science data. The GCMD staff will be responsible for determining the appropriateness for inclusion and for the quality control of the entries by working with service providers. 

    2) A four level hierarchy of Services keywords will be maintained, positioned as CATEGORY/TOPIC/TERM/SERVICE SPECIFIC NAME. 

    3) All keywords at the four levels of hierarchy should be parallel and 'mutually exclusive'.The GCMD keyword authorities will determine if modifications or additions are appropriate. All modifications or additions must strictly adhere to the rules contained herein. 

    4) Services should be classified by their primary purposes. Existing service keywords at the TOPIC/TERM/VARIABLE level will be used to associate the services that apply to the SERF.The summary can be used for further clarification. Providers may not submit more than one entry (SERF) for any one service. 

    5) Existing science keywords at the TOPIC/TERM/VARIABLE level will be used to associate the service with a science TOPIC/TERM/VARIABLE.

 

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This document should be cited as:
Service Entry Resource Format (SERF) Writer's Guide, 2008.
Global Change Master Directory. National Aeronautics and Space Administration. [http://gcmd.nasa.gov/User/serfguide/].