Emerging Metadata Standards

1
Emerging Metadata Standards
escholarship.cdlib.org/rtennant/presentations/2003
ptpl/metadata/

• Roy Tennant

2
Outline

• Foundational Standards
• Conceptual Frameworks
• Descriptive Metadata Standards (but not an
  exhaustive list)
• Transfer Standards Protocols
• Software Components
• Advice to Catalogers
• If You Remember Nothing Else

3
Foundational Standards

• XML
• XSLT
• XHTML
• CSS

4
XML

• A simple and yet powerful way to encode
  information in a structured format for processing
  and communication
• All emerging metadata standards are encoded in
  XML, and many legacy ones have XML encodings,
  including MARC
• Also, all kinds of hot new protocols and services
  use it, from OAI-PMH to RSS and SRU/SRW even
  library catalog systems
• LEARN XML NOW!
• Did I mention how important XML is?

5
XSLT

• XML Stylesheet Language Transformations
• The method by which XML-encoded information can
  be processed and/or transformed into other
  formats (e.g., HTML for web browser display)
• A powerful set of mechanisms for selecting
  specific chunks of XML and processing it
• Some standard programming structures are
  including looping, decision structures, etc.

6
XSLT Demonstration
7
XHTML

• An XML-compliant HTML
• Requires the use of Cascading Stylesheets (CSS)
  for styling (no FONT shenanigans!)
• Key benefits
• Clean code!
• You can easily make global display changes
• With such a highly structured format, migration
  over time is much simplified
• All new HTML should be XHTML!

8
Cascading Style Sheets (CSS)

• The method by which web browsers can apply a
  particular display to XML or HTML (in particular,
  XHTML)
• Simple, straightforward syntax
• h1, h2, h3
• color 005A9C
• Plenty of examples available

9
Putting It All Together
Transformation
Information
Presentation
XSLT Stylesheet
XML
XHTML representation
XML Processor
Cascading Stylesheet (CSS)
Web Server
10
Conceptual Frameworks

• Namespaces
• FRBR

11
Namespaces

• A method to keep metadata elements from different
  schemas from colliding
• Example the tag ltnamegt may have a very different
  meaning in different standards
• A namespace declaration specifies from which
  specification a set of tags is drawn

ltmets xmlns"http//www.loc.gov/METS/"
xsischemaLocation "http//www.loc.gov/standards/
mets/mets.xsd"gt
12
FRBR

• Functional Requirements for Bibliographic Records
  (from IFLA, prounounced ferber)
• A method by which we can bring together for the
  user multiple records that describe one
  intellectual object
• Example system Redlightgreen.com from RLG

13
(No Transcript)
14
(No Transcript)
15
Descriptive Metadata Standards

• Dublin Core
• Resource Description Framework (RDF)
• (MODS)

16
Dublin Core

• A common meeting ground for more complex metadata
  standards
• Co-developed by an international community of
  librarians and computer scientists (broad-based
  support)
• Example of success it is the one required
  metadata format for OAI-PMH
• Remember this is not meant for most internal
  uses, but for external sharing of metadata

17
ONIX

• A descriptive standard from the publishing
  community
• Optimized for simple book descriptions, publisher
  information, rights, purchasing information, etc.
• Could serve as a proto-record from which we can
  build a richer bibliographic record

18
RDF

• Resource Description Framework
• A standard for encoding entities and
  relationships between those entities in a web
  environment
• A resource is anything that can be described by
  a Uniform Resource Identifier (URI)
• A resource can have one or more properties
• Relationships between resources are depicted in
  XML-encoded statements

ltrdfDescription about'http//www.textuality.com/
RDF/Why-RDF.html'gt ltAuthorgtTim Braylt/Authorgt
ltHome-Page rdfresource'http//www.textuality.co
m' /gt lt/rdfDescriptiongt
19
MODS

• Metadata Object Descripion Schema, from the
  Library of Congress
• A bibliographic standard similar to MARC
  expressed in XML
• Probably the closest thing to a replacement for
  MARC
• Currently used as an alternative to MARC XML

20
Transfer Standards Protocols

• METS
• RSS
• OAI-PMH
• SOAP (REST)
• SRU/SRW

21
METS

• Metadata Encoding and Transmission Schema
• An XML wrapper for various metadata packages,
  as well as component files or the internal
  structure of a file
• Increasingly used as an all-purpose metadata
  package for digital objects

22
(No Transcript)
23
RSS

• Pick your acronym definition Really Simple
  Syndication (my fave), Rich Site Summary (from
  Netscape), or RDF __ (for those into the RDF
  version of RSS)
• Useful for current awareness
• Blog readers
• Automatic web site updates

24
(No Transcript)
25
(No Transcript)
26
(No Transcript)
27
OAI-PMH

• A protocol for harvesting (as opposed to
  searching) metadata from content repositories
• A digital library interoperability home run
• Simple, easy to implement and understand other
  uses are being layered on top (e.g., dynamic
  searching)

28
(No Transcript)
29
(No Transcript)
30
Web Services SOAP REST

• SOAP Simple Object Access Protocol
• A lightweight way to exchange encoded information
  between applications
• REST (Representational State Transfer) is a URL
  (HTTP Get) based way of sending a SOAP request
  and receiving an XML-encoded response
• Both Google and Amazon can be searched via Web
  Services

31
SOAP Request
POST /InStock HTTP/1.1 Host www.stock.org Content
-Type application/soapxml charsetutf-8 Content
-Length nnn lt?xml version"1.0"?gt ltsoapEnvelope
xmlnssoap"http//www.w3.org/2001/12/soap-envelo
pe" soapencodingStyle"http//www.w3.org/2001/12/
soap-encoding"gt ltsoapBody xmlnsm"http//www.
stock.org/stock"gt ltmGetStockPricegt
ltmStockNamegtIBMlt/mStockNamegt
lt/mGetStockPricegt lt/soapBodygt lt/soapEnvelope
gt
32
SOAP Response
HTTP/1.1 200 OK Content-Type application/soap
charsetutf-8 Content-Length nnn lt?xml
version"1.0"?gt ltsoapEnvelope xmlnssoap"http//
www.w3.org/2001/12/soap-envelope" soapencodingSty
le"http//www.w3.org/2001/12/soap-encoding"gt
ltsoapBody xmlnsm"http//www.stock.org/stock"gt
ltmGetStockPriceResponsegt
ltmPricegt34.5lt/mPricegt lt/mGetStockPriceRespo
nsegt lt/soapBodygt lt/soapEnvelopegt
33
(No Transcript)
34
SRU/SRW

• A Web Services-based replacement for Z39.50
• SRW submitted as an XML package (uses HTTP
  POST)
• SRU carried by a URL (uses HTTP GET)
• The best chance Z39.50 has of surviving
  metasearch services will likely use it as an XML
  replacement for Z39.50

35
Software Components

• XML Parsers
• Databases
• Protocol Engines (clients and servers, e.g.,
  OAI-PMH modules, Web Services components)
• Error checking and normalization routines

36
Advice to Catalogers

• Learn to like any metadata you see (If you cant
  be with the metadata you love, love the one
  youre with or I never metadata I didnt like)
• Think of new ways to exploit metadata
• We need your skills, but you must be there for us
  apply what you know to a new environment

37
If You Remember Nothing Else

• XML it is foundational to all modern metadata
  standards
• Learn to like any metadata you see (if you dont
  already)
• Be flexible, and never stop learning!