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5. Entity and Attribute Information
Entity and Attribute Information provides details about the information content of the data set, including the entity types, their attributes, and the domains from which attribute values may be assigned.
"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 the 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." 1
This section contains definitions and examples for the following metadata elements.
Detailed Description
Overview Description
Detailed Description
Detailed Description provides a description of the entities, attributes, attribute values, and related characteristics encoded in the data resource. This metadata element encompasses the following sub-elements.
Entity Type
The definition and description of a set into which similar entity instances are classified.
Entity Type Label
Definition: The name of the entity type.
Format: Free text.
Example:
Entity Type Label: wetland
Entity Type Definition
Definition: The description of the entity type.
Format: Free text.
Example:
Entity Type Definition: Wetlands are lands transitional between terrestrial and aquatic systems where the water table is usually at or near the surface or the land is covered by shallow water. For purposes of this classification wetlands must have one or more of the following three attributes: 1) at least periodically, the land supports predominantly hydrophytes; 2) the substrate is predominantly undrained hydric soil; and 3) the substrate is non-soil and is saturated with water or covered by shallow water at some time during the growing season of each year.
Entity Type Definition Source
Definition: The authority of the definition.
Format: Free text.
Example:
Entity Type Definition Source: Cowardin, L. M., Carter, F. Golet, and E. LaRoe. 1979. Classification of wetlands and deepwater habitats of the United States. U.S. Fish and Wildlife Service. 103 pp.
Attribute
A defined characteristic of an entity.
Attribute Label
Definition: The name of the attribute.
Format: Free text.
Example:
Attribute Label: wetland classification
Attribute Definition
Definition: The description of the attribute.
Format: Free text.
Example:
Attribute Definition: The wetland classification system is hierarchical, with wetlands and deepwater habitats divided among five major systems at the broadest level. The five systems include Marine (open ocean and associated coastline), Estuarine (salt marshes and brackish tidal water), Riverine (rivers, creeks, and streams), Lacustrine (lakes and deep ponds), and Palustrine (shallow ponds, marches, swamps, sloughs). Systems are further subdivided into subsystems which reflect hydrologic conditions. Below the subsystem is the class which describes the appearance of the wetland in terms of vegetation or substrate. Each class is further subdivided into subclasses; vegetated subclasses are described in terms of life form and substrate subclasses in terms of composition. The classification system also includes modifiers to describe hydrology (water regime), soils, water chemistry (pH, salinity), and special modifiers relating to man's activities (e.g. impounded, partly drained).
Attribute Definition Source
Definition: The authority of the definition.
Format: Free text.
Example:
Attribute Definition Source: Cowardin, L, M., Carter, F. Golet, and E. LaRoe. 1979. Classification of wetlands and deepwater habitats of the United States. U.S. Fish and Wildlife Service. 103 pp.
Attribute Domain Values
The valid values that can be assigned for an attribute.
Enumerated Domain
The members of an established set of valid values.
Enumerated Domain Value
Definition: The name or label of a member of the set.
Format: Free text.
Enumerated Domain Value Definition
Definition: The description of the value.
Format: Free text.
Enumerated Domain Value Definition Source
Definition: The authority of the definition.
Format: Free text.
Range Domain
The minimum and maximum values of a continuum of valid values.
Range Domain Minimum
Definition: The least value that the attribute can be assigned.
Format: Free text.
Example:
Range Domain Minimum: 4.82
Range Domain Maximum
Definition: The greatest value that the attribute can be assigned.
Format: Free text.
Example:
Range Domain Maximum: 23.71
Codeset Domain
Reference to a standard or list which contains the members of an established set of valid values.
Codeset Name
Definition: The title of the codeset.
Format: Free text.
Example:
Codeset Name: USFWS-NWI wetland classification codeset.
Codeset Source
Definition: The authority for the codeset.
Format: Free text.
Example:
Code Source: Photointerpretations Conventions for the National Wetlands Inventory, March 1990.
Unrepresentable Domain
Definition: A description of the values and reasons why they cannot be represented.
Format: Free text.
Attribute Units of Measure
Definition: The standard of measurement for an attribute value.
Format: Free text.
Example:
Attribute Units of Measure: percent by weight
Attribute Units of Measure: grams
Attribute Units of Measure: cm
Attribute Measurement Resolution
Definition: The smallest unit increment to which an attribute value is measured.
Format: Attribute Measurement Resolution > 0.0
Example:
Attribute Measurement Resolution: 0.1
Attribute Measurement Resolution: 1
Beginning Date of Attribute Values
Definition: The earliest or only date for which the attribute values are current. In cases when a range of dates are provided, this is the earliest date for which the information are valid.
Format: Free date.
Ending Date of Attribute Values
Definition: The latest date for which the information are current. Used in cases when a range of dates are provided.
Format: Free date.
Attribute Value Accuracy Information
An assessment of the accuracy of the assignment of attribute values.
Attribute Value Accuracy
Definition: An estimate of the accuracy of the assignment of attribute values.
Format: Free text.
Attribute Value Accuracy Explanation
Definition: The definition of the Attribute Value Accuracy measure and units, and a description of how the estimate was derived.
Format: Free text.
Attribute Measurement Frequency
Definition: The frequency with which attribute values are added.
Format: Select from list: Unknown, As needed, Irregular, None planned; or free text.
Example:
Attribute Measurement Frequency: As needed
Attribute Measurement Frequency: Based on periodic review.
Overview Description
Overview Description contains a summary of the information content of the data set, and a reference to the source(s) of the complete description. This metadata element encompasses the following sub-elements.
Entity and Attribute Overview
Definition: A detailed summary of the information contained in a data set.
Format: Free text.
Example:
Entity and Attribute Overview: The DLG-3 scheme assigns any number of attribute codes to spatial objects. Some DLG-3 attribute codes identify real world entities, other codes represent attributes of those entities. Hydrography (major code: 050) contains information about streams, bodies of water, wetlands, coastal waters, and water used for transportation. Vegetative features, which are associated with wetlands or submerged areas, are included, as are manmade hydrologic features. The direction of the water flow is captured. This information is not collected for specific hydrologic studies or for navigational assistance. The SDTS model of spatial phenomena describes the real world as consisting of entities which are characterized by attributes which have attribute values. DLG-3 does not explicitly use this entity-attribute-attribute value model. The SDTS implementation of DLG-3 identifies which DLG-3 attribute codes identify entities and which identify attributes of those entities.
Entity and Attribute Detail Citation
Definition: Reference to the complete description of the entity types, attributes, and attribute values for the data set.
Format: Free text.
Example:
Entity and Attribute Detail Citation: The USGS document Standards for Digital Line Graphs, Part 3: Attribute Codes, contains a detailed description of each attribute code and a reference to the associated map symbols on the map source materials.
References
1 Federal Geographic Data Committee (FGDC). 1995. Content Standards for Digital Geospatial Metadata. Workbook (March 24). Washington, D.C.: FGDC. pp.5-1.
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