Metadata
Tom Worthington FACS HLM
Metadata
The Oxford English Dictionary describes metadata as:
metadata n., a set of data that describes and gives
information about other data...
[1968 Proc. IFIP 4th Congr.: Suppl. 10 I. 113/2 There are
categories of information about each data set as a unit in a
data set of data sets, which must be handled as a special meta
data set.] 1987 Philos. Trans. Royal Soc. A. 322 373 The
challenge is to accumulate data..from diverse sources, convert
it to machine-readable form with a harmonized array of
*metadata descriptors and present the resulting database(s) to
the user. 1998 New Scientist 30 May 35/2 With XML, attaching
metadata to a document is easy, at least in theory.
Oxford English Dictionary, (Online) Draft
entry Dec. 2001, URL: http://dictionary.oed.com/cgi/entry/00307096/00307096se19
Metadata can be described simply as
"Data about Data". As an example the
"creator" of this document is "Tom
Worthington". The data is "Tom Worthington" and
the medadata is "creator".
Metadata provides standard data items to allow parties to
communicate about their organisations, products, terms and
conditions. The payment and the "money" itself consists
of data in an agreed metadata format, in an electronic
transaction. Without suitable metadata standards, e-commerce
could not take place and "money" in our online
financial systems would cease to exist.
Metadata can also be used to describe published documents. The
use of metadata for e-commerce and for publishing has converged
in the last few years with the use of the same XML technology for
both applications.
Australian Government Metadata
<meta name="DC.Publisher"
scheme="X500" content="ou=Australian Government
Information Management Office (AGIMO) ; o= Commonwealth of
Australia ; c=AU">
<meta name="DC.Description" content="The
australia.gov.au website is your connection with government in
Australia...">
<meta name="DC.Subject" scheme="TAGS"
content="Government information; Federal government;
Government services; Government publications; Web
sites">
<meta name="DC.Type.documentType"
scheme="agls-document"
content="homepage">
From: "australia.gov.au : your
connection with government", Australian Government
Information Management Office, 2004-06-30, URL: http://www.australia.gov.au/
Tax Office e-commerce transaction
<FORM_PERIOD_LABEL_TEXT>July to September
2001</FORM_PERIOD_LABEL_TEXT>
<EFT_CODE> 51111 121 059 9059</EFT_CODE>
<BILLER_CODE>75556</BILLER_CODE>
<PAYG_WITHHOLDING>0</PAYG_WITHHOLDING>
<PAYG_INSTALMENT>12541</PAYG_INSTALMENT>
<DEFERRED_COMPANY_FUND_INSTALMENT>7879801
</DEFERRED_COMPANY_FUND_INSTALMENT>
<TOTAL_DEBITS>7892342</TOTAL_DEBITS>
<TOTAL_CREDITS>0</TOTAL_CREDITS>
<NET_AMOUNT_FOR_THIS_STATEMENT>7892342
</NET_AMOUNT_FOR_THIS_STATEMENT>
<GST_LABEL_TEXT>for the QUARTER from 1 Jul 2001 to 30 Sep
2001</GST_LABEL_TEXT>
<GST_ACCOUNTING_METHOD_LABEL_TEXT>Cash ...
From: Formatting the eBAS with XSL, Tom
Worthington, 29 November 2002, URL: http://www.tomw.net.au/2002/atoxml.html
This is an example of an e-commerce transaction. This is an
Australian Taxation Office electronic tax form for the Goods and
Services Tax (GST).
Dublin Core
| Title |
Typically, Title will be a name by which the resource
is formally known. |
| Creator |
Examples of Creator include a person, an organization,
or a service. ... |
| Subject |
... keywords, key phrases or classification codes that
describe a topic of the resource. Recommended best practice
is to select a value from a controlled vocabulary or formal
classification scheme. |
| Description |
... an abstract, table of contents, reference to a
graphical representation of content or a free-text account
of the content. ... |
Adapted from "Dublin Core Metadata
Element Set", Version 1.1: Reference Description, DCMI,
2003-06-02, URL: http://dublincore.org/documents/dces/
Dublin
Core (DC)is a metadata standards project originating from a
workshop held in Dublin, Ohio, USA in 1995. "Dublin
Core" metadata element set is a small set of metadata
definitions intended for cross-domain information resources.
However, DC has its origins in the work of librarians and so
tends to work better for describing printed text, than other
items, such as video.
The intention with DC is to provide a brief standard set of
essential metadata items for resources: Title, Creator, Subject,
Description, Publisher, Contributor, Date, Type, Format,
Identifier, Source, Language, Relation, Coverage, Rights.
Other examples of controlled vocabulary are using the Internet
Media Types (MIME) for
defining computer media formats in the format element and
language tags, such as "en-AU" for Australian
English.
AGLS
|
Element
|
Example
|
|
Function
|
<META NAME="AGLS.Function"
CONTENT="School Education">
|
|
Availability
|
<META NAME="AGLS.Availability"
CONTENT="Medical assistance is available by
contacting the after hours hotline on ...">
|
|
Audience
|
<agls:audience>anglers</agls:audience>
|
|
Mandate
|
<META NAME="AGLS.Mandate.case"
SCHEME="URI"
CONTENT="http://...">
|
Complied from AGLS Metadata Element Set,
Part 2: Usage Guide, Version 1.3 , National Archives of
Australia, 2002, URL:
http://www.naa.gov.au/recordkeeping/gov_online/agls/metadata_element_set.html
The
Australian Government Locator Service (AGLS) metadata
standard is a set of 19 descriptive elements to improve the
visibility and accessibility of services and information over the
Internet. The AGLS standard is based the 15 Dublin Core elements,
plus four extra elements.
No elements are mandatory for DC, but AGLS requires five (or
six) of these.
Qualifiers
Qualifiers are additions and extensions to the metadata
elements that give metadata creators the option to refine the
semantics of the element set, and add precision to the values
of the metadata elements. For example, it may be useful to
indicate that the value has been selected from a particular
controlled vocabulary, such as a list of keywords, or is
encoded using a particular convention - the format for dates is
an important case - or in a particular natural language.
From: AGLS Metadata Element Set, Part 2:
Usage Guide, Version 1.3 , National Archives of Australia, 2002,
URL:
http://www.naa.gov.au/recordkeeping/gov_online/agls/metadata_element_set.html
Qualifiers are used to restrict the semantics of the
relationship between the resource and the element value. AGLS
encourages more use of qualifiers than DC, but does not require
it.
AGLS Qualifiers
AGLS uses two types of qualifiers:
-
Element refinements are represented in
HTML <meta> syntax with qualifiers appended to to the
element names. For example:
"DC.Type.documentType".
-
Encoding schemes indicate how the value
is to be interpreted if it has been chosen from a controlled
vocabulary, or externally defined standard. For example:
<META NAME="DC.Date.modified"
SCHEME="ISO8601"
CONTENT="1998-08-27">.
Metadata Tools
This is a demonstration of DSTC's Reg metadata editor.
Reg allows you to:
- enter metadata
- export metadata in a number of syntaxes
- save metadata records to a test repository
- reload metadata records from a repository for
editing
Reg uses metadata schemas to customize itself for different
metadata element sets. ...
"Reg - Metadata Editor", DSTC
Pty Ltd, 1998, 2000, URL: http://metadata.net/cgi-bin/reg/demo.cgi.
Metadata is rarely entered be the document author typing in
text. When encoded in the header of a HTML document the metadata
is not displayed by a web browser. Specialized software, such as
a content management systems, or features in word processors are
used to enter and display the metadata. The user of the system is
likely to be unaware they are using a metadata standard or how it
is encoded. Examples of how these systems will be shown
later.
The Distributed Systems Technology Centre (DSTC Pty Ltd), has
produced a metadata tool to create AGLS and Dublin Core metadata.
Rege, can be
used to generate AGLS metadata syntax. This would be too
cumbersome for creating real metadata, but is a useful way to
learn about the process.
