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Implementing Effective Metadata
Brian LavoieOffice of Research
OCLC Online Computer Library Center, Inc.
Intranets ‘99, San Francisco
April 27, 1999
Roadmap
I. Metadata for Networked Resources
II. Implementing Metadata in HTML Documents
III. Metadata Element Sets
IV. The Dublin Core: Overview and Implementation in HTML
V. Summary
Metadata
• “Data that provides information about a resource”– to manage information collections– to facilitate resource discovery
• Can be created for information resources of any kind, in any medium … for example:– Books: bibliographic data in a card catalog– Computer programs: comments in source code
Metadata for Networked Resources
Why metadata?
Problem: Rapid growth in networked resources leads to increasingly chaotic information collections.– As size and scope of collection expands, simple keyword indexing
becomes less effective.
Solution: Need metadata framework that:– enables richer description than keyword indexing.– is usable by content managers who are not necessarily resource
description specialists.– is simple and inexpensive to implement.
HTML (Hypertext Markup Language)
Tag-based markup language for structured, “hyperlinked” documents
<HTML>
<HEAD>
<TITLE>My Document</TITLE>
</HEAD>
<BODY>
<P><B>A Sample HTML Document</B>
<P><A HREF=“http://www.oclc.org”>Click here</A>
</BODY>
</HTML>
Implementing Metadata in HTML Documents
The META tag:
Container for embedded resource description
<HEAD>
<META name=“…” content=“...”>
</HEAD>
Name Attribute = property or characteristic of a resource
(e.g., title, author, keywords)
Content Attribute = specific value of a property
(e.g., “War and Peace”, Leo Tolstoy, Russian literature)
META Tag Usage: Example
http://www.onlineinc.com/intranets/
<META name=“keywords” content=“intranet,
intranets, knowledge management,
knowledge worker, knowledge workers,
information professional,
information professionals”>
<META name=“description”
content=“Intranets ‘99 Conference”>
HTMLDocument
The META Tag and Search Engines
Enter:
+intranets +“information professionals”
into AltaVista search engine … returns:
Intranets ‘99
Intranets '99 Conference
URL: www.onlineinc.com/intranets/index.html
Last modified 17-Dec-98 - page size 5K - in
English [Translate]
Inconsistency Across Name Attribute Values
• <META NAME=“KEY WORDS” …
• <META NAME=“KEYPHRASES” …
• <META NAME=“KEYS” …
• <META NAME=“KEYWORD” …
• <META NAME=“KEYWORDS” …
Inconsistency Across Content Attribute Values
<META NAME="AUTHOR” …
… CONTENT="OAKWOOD DESIGN">
… CONTENT="JJR ENTERPRISES - [email protected]">
… CONTENT="TIM SCHAEFER, [email protected] COPYRIGHT 1997, 1998 ALL RIGHTS RESERVED">
… CONTENT="RWM 980602">
… CONTENT="CLOTHING">
The META Tag: Pros and Cons
PROS...• Useful container for embedded resource description.• Easily adapted for use by automated document management
or search/retrieval applications.
CONS...• No guidelines on how to “fill out” the tag. Prone to
inconsistency and misusage.
Need to supplement the META tag with a more structured
approach to the metadata itself ...
Metadata Element Sets
• A set of descriptive elements with well-defined interpretations (semantics) that collectively form a description of a resource.
• Eliminates inconsistencies and enhances the usefulness of metadata in managing and locating resources, by describing resources in a standard, consistent way.
The Dublin Core Metadata Initiative
• Metadata element set intended to facilitate description and discovery of electronic resources.
• Usable by non-experts, as well as resource description specialists.
• Extensible, for richer resource descriptions. • Development has benefited from participation of an
international cross-section of communities: libraries, museums, government agencies, corporations...
The 15 Dublin Core Metadata Elements
Title Author or Creator
Subject and Keywords Description
Publisher Other Contributor
Date Resource Type
Format Resource Identifier
Source Language
Relation Coverage
Rights Management
Implementing Dublin Core:The META Tag Revisited
HTML Metadata Container: <META name=“…” content=“…”>
<HTML>
<HEAD>
<META name=“DC.Title” content=“Employee Benefits Manual”>
<META name=“DC.Creator” content=“Joe Smith”>
<META name=“DC.Publisher” content=“XYZ Corporation”>
</HEAD>
<BODY>
...
</BODY>
<HTML>
Extending the Dublin Core
• Sometimes more detailed description of a resource is needed than the 15 core elements can provide.
• Dublin Core can be extended with qualifiers:
<META name=“DC.Date.Created” content=“1999-01-20”>
<META name=“DC.Date.Issued” content=“1999-01-31”>
More Ways to Clarify Metadata
• <META name=“DC.Identifier” content=“0-8230-2355-9”>
• <LINK rel=“schema.DC” href=“http://purl.org/DC/elements/1.0/”>
<META name=“DC.Identifier” content=“0-8230-2355-9”>
• <LINK rel=“schema.DC” href=“http://purl.org/DC/elements/1.0/”>
<META name=“DC.Identifier” scheme=“ISBN” content=“0-8230-2355-9”>
Metadata in Action:http://www.gilderlehrman.com
Gilder Lehrman Exhibition Calendar
Embedded Metadata<META name="DC.Title” content=”Exhibitions Calendar of Gilder Lehrman
Documents">
<META name="DC.Creator" content="Paul Romaine, The Gilder Lehrman Collection">
<META name="DC.Subject" content=”Calendar, exhibitions in New York, ...">
<META name="DC.Description" content=”Calendar of exhibitions, principally...">
<META name="DC.Publisher" content="The Gilder Lehrman Collection">
<META name="DC.Contributor" content=”Robert Parks, Pierpont Morgan Library">
<META name="DC.Date" content="1999-04-21">
<META name="DC.Type" content=”Bibliography">
<META name="DC.Format" content="text/html">
<META name="DC.Identifier” content="http://www.gilderlehrman.com/HTM/exhibitions/index.html">
<META name="DC.Language" content="English">
Derived Metadata Record
Title: Exhibitions Calendar of Gilder Lehrman Documents
Creator: Paul Romaine
Subject: Calendar, exhibitions in New York, ...
Description:Calendar of exhibitions, principally in New York ...
Publisher: The Gilder Lehrman Collection
Contributor:Robert Parks
Date: 1999-04-21
Type: Bibliography
Format: text/html
Identifier: http://www.gilderlehrman.com/HTM/exhibitions/index.html
Language: English
Summary:Implementing Effective Metadata
Implementing Metadata: • META tag provides framework for deploying metadata as
embedded resource description in HTML documents.
Implementing Effective Metadata:• Use a well-defined metadata element set.• Dublin Core offers rich description; usable by description
experts and non-experts; simple and inexpensive to implement.• Clarify potentially ambiguous metadata with LINK tag and
scheme attribute.
For More Information...
• META Tag:
http://www.w3.org/TR/REC-html40/
• Metadata:
http://www.w3.org/Metadata
• Dublin Core:
http://purl.org/dc