Metadata Standards Development

• 1. Overview
• 1.1 About The Standard
• 1.2 The Major Uses of Metadata
• 2. Characteristics That Define The Role of Metadata
• 2.1 Definitions of Data Elements
• 2.2 Development of the Standard
• 3. An Example of the Implementation
• 3.1 Obtaining Copies of the Standard

Support Activities for the FGDC....Tasks, Tools, Sites

FGDC Public Metadata Documents Online

The Metadata Standard in ImageMap Form

A Metadata Validation Tool

Visit the on-line Metadata Discussion.

Content Standards for Digital Geospatial Metadata

1. Overview

At its June 8, 1994, meeting, the Federal Geographic Data Committee (FGDC) approved the "Content Standards for Digital Geospatial Metadata." Metadata, or "data about data," describe the content, quality, condition, and other characteristics of data. The standard specifies the information content of metadata for a set of digital geospatial data. The purpose of the standard is to provide a common set of terminology and definitions for documentation related to these metadata. access control disabled, clients can connect from any host q!: Command not found. their geospatial data. The main reason to document data is to maintain an organization's investment in its geospatial data. Organizations that do not document their data often find that, over time or because of personnel changes, they no longer know the content or quality of their data. Organizations then cannot trust the results generated from the data in which they have invested their time and resources. In addition, the lack of information about other organizations' data often leads to a needless duplicating of effort.

The standard specifies information that helps prospective users to determine what data exist, the fitness of these data for their applications, and the conditions for accessing these data. Metadata also aid the transfer of data to other users' systems.

On April 11, 1994, President Clinton signed Executive Order 12906, "Coordinating Geographic Data Acquisition and Access: The National Spatial Data Infrastructure." This executive order instructs Federal agencies to use the standard to document new geospatial data beginning in 1995, and to provide these metadata to the public through the National Geospatial Data Clearinghouse.

RETURN to Index

1.1 About The Standard

The standard provides a common set of terminology and definitions for the documentation of geospatial data. The standard establishes the names of data elements and groups of data elements to be used for these purposes, the definitions of these data elements and groups, and information about the values that are to be provided for the data elements. Information about terms that are mandatory, mandatory under certain conditions, and optional (provided at the discretion of the data provider) also is provided by the standard.

RETURN to Index

1.2 The Major Uses of Metadata are:

• To help organize and maintain an organization's internal investment in spatial data,
• To provide information about an organization's data holdings to data catalogues, clearinghouses, and brokerages, and
• To provide information to process and interpret data received through a transfer from an external source.

RETURN to Index

2. Characteristics That Define The Role of Metadata

• Availability - data needed to determine the sets of data that exist for a geographic location.
• Fitness for use - data needed to determine if a set of data meets a specified need.
• Access - data needed to acquire an identified set of data.
• Transfer - data needed to process and use a set of data.

These characteristics form a continuum in which a user moves through a number of choices to determine what data are available, to evaluate the fitness of, to acquire, transfer and process the data. The order in which data elements are evaluated, and the relative importance of the data elements, will not be the same for all users or for all tasks that use metadata. In addition, users with different tasks or at different stages of evaluation may require (or prefer) that a set of information be available at different levels of abstraction or in different forms.

RETURN to Index

2.1 Definitions of Data Elements

• Identification Information - basic information about the data set. Examples include the title, the geographic area covered, currentness, and rules for acquiring or using the data.

• Data Quality Information - an assessment of the quality of the data set. Examples include the positional and attribute accuracy, completeness, consistency, the sources of information, and methods used to produce the data. Recommendations on information to be reported and tasks to be performed are in the Spatial Data Transfer Standard (Federal Information Processing Standard 173) (1992).

• Spatial Data Organization Information - the mechanism used to represent spatial information in the data set. Examples include the method used to represent spatial positions directly (such as raster or vector) and indirectly (such as street addresses or county codes) and the number of spatial objects in the data set.

• Spatial Reference Information - description of the reference frame for, and means of encoding, coordinates in the data set. Examples include the name of and parameters for map projections or grid coordinate systems, horizontal and vertical datums, and the coordinate system resolution.

• Entity and Attribute Information - information about the content of the data set, including the entities types and their attributes and the domains from which attribute values may be assigned. Examples include the names and definitions of features, attributes, and attribute values.

• Distribution Information - information about obtaining the data set. Examples include a contact for the distributor, available formats, information about how to obtain data sets online or on physical media (such as cartridge tape or CD-ROM), and fees for the data.

• Metadata Reference Information - information on the currentness of the metadata information and the responsible party. Examples include currentness and information about the organization that provided the metadata.

The standard has sections that specify contact information for organizations or individuals that developed or distribute the data set, temporal information for time periods covered by the data set, and citation information for the data set and information sources from which the data set was derived.

The standard does not specify how this information is organized in a computer system or in a data transfer, nor the means by which this information is transmitted or communicated to the user. The variety of means of organizing data in a computer or in a transfer, the differences between data providers to describe their data holdings because of varying institutional and technical capabilities, and the rapid evolution of means to provide information through the Internet for different purposes determined this decision.

RETURN to Index

2.2 Development of the Standard

The FGDC initiated work on the standard in June, 1992, with a forum on spatial metadata. At the forum, the participants agreed on the need for a standard on information content for metadata about spatial data. A committee of volunteers developed an initial draft content standard. This draft was slightly revised and offered for public review from October 1992 to April 1993. Extensive comments were received from the public. The FGDC's Standards Working Group revised the draft, which was provided for further review and testing in July 1993. Revised drafts were reviewed and tested again in January, March, and May 1994. The standard was approved by the FGDC on June 8, 1994.

RETURN to Index

3. An Example of the Implementation

RETURN to Index

3.1 Obtaining Copies of the Standard

Please Contact:

The standard is also available by anonymous file transfer protocol (FTP) from:

www.fgdc.gov (130.11.52.153) under /pub/metadata

RETURN to Index