What is the purpose of the Entity and Attribute Information section?

Users of a data set need to know the meaning of entity, attribute, and attribute value information associated with the spatial information. For example, a data set might include the entity "road". A "road" might have the attribute "road type", which can be assigned the attribute values of "heavy duty", "medium duty", "light duty", or "trail". The producer of the data set may have different definitions for "road", "road type", "heavy duty", "medium duty", "light duty", and "trail" than a user. The Entity and Attribute Information section provides the way for a producer to describe the meaning of this nonspatial entity, attribute, and attribute value information so a user can understand the information content of a data set and use the data appropriately.

What is the difference between the Detailed Description and Overview Description elements?

As stated above, users must have access to the meanings of the entities, attributes, and attribute values in a data set. The Detailed Description provides the elements needed to describe these meanings.

In developing the metadata standards, reviewers noted that they often had complete data dictionaries for their entity, attribute, and attribute value information, and preferred to refer to the existing descriptions instead of duplicating them. The Overview Description provides the elements needed to give users a sense of the information content and a reference to the source(s) of the complete description. Note that the Overview Description does not relieve the producer of the responsibility to provide a complete description. The Overview Description elements refer to the source of the complete description, and do not allow a producer merely to summarize the information content.

The two approaches can be used together to document a data set. The Overview Description would be used to describe data for which a complete description is available elsewhere; the Detailed Description would be used to describe data for which a complete description has not been compiled elsewhere.

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