Metadata
Introduction
Metadata, which is literally “data about data,” is structured information describing a resource. Metadata is used to
- find,
- gather
- maintain resources over long periods of time.
Metadata can describe a variety of information such as: the subject matter of the resource; the creators of the resource; the legal rights to the resource; the technical information to store and access the resource.
Consistent application of descriptive metadata contributes to online search success and makes information retrieval within a single collection (or across multiple collections) more reliable. Metadata is also important to the documentation and maintenance of interrelationships between information resources. Administrative, technical, and preservation metadata can all contribute to the management of information resources and helps to ensure their intellectual integrity.
“Introduction to Metadata” PowerPoint presentation by Jan Addison, July 2005
Metadata in Contentdm collections
Most descriptive metadata be mapped to the Dublin Core metadata standard. In the administrative module of Contentdm, the administrator begins with Simple DC elements, and may add or delete fields to suit each collection. A grid of metadata choices may look like this:
Field properties |
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For each field, choices are made to map content to a specific Dublin Core element; hide or display data; make fields searchable or not; and apply a controlled vocabulary to the field or not.
Standards
Format standard: Dublin Core. For a discussion, refer to:
Dublin Core Usage in Contentdm, Purdue University Libraries
Descriptive standards: Describing Archives : a Content Standard; Anglo-American Cataloging Rules, 2nd ed., rev.
Subject headings: Thesaurus for Graphic Materials I (subjects) and II (form/genre terms).
Names: Library of Congress Name Authority File
Preservation Metadata
Preservation metadata is the information infrastructure that supports the processes associated with digital preservation. It is the information necessary to maintain the viability, renderability, and understandability of digital resources over time.
In the table below, the Digital Initiatives Team discussed the 16 preservation elements from RLG’s document Working Group on Preservation Issues of Metadata, Final Report http://www.oclc.org/programs/ourwork/past/digpresmetadata/report.htm (page viewed 12/21/2006).
Purdue Libraries recognizes the TIFF file as the digital master, and assumes 0 compression.
TIFF |
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Element |
Example |
Currently capture |
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Date |
yyyyddmm |
Y/incorrect format |
|
Transcriber |
Purdue University Libraries, ASC |
N |
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Producer |
Purdue University Libraries, ASC |
N |
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Capture device |
Kronton 3012 |
Y/Silverfast N/Photoshop |
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Capture details |
PixelCraft Proimager 8000 |
Y |
|
Change history |
Orig. dig. master image mig. from TIFF v.X to.. |
N |
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Validation key |
Standard internet checksum |
N |
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Encryption |
RSA Public Key Cryptosystem |
N |
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Resolution |
600 dpi |
Y |
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Source |
1 photograph : b&w ; 18 x 22 cm. |
Y/dimensions |
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Color |
8-bit |
Y |
|
Color management |
Softproof (Photoshop Plugin) |
N |
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Color bar/Gray scale bar |
Kodak Z60 Color Input Target |
N |
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Control targets |
AIIM Scanning TEST Chart #2 |
N |
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ja/DIGITs 10/3/2005 rev 10/14 |
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Finally the DIGITs team chose the following preservation metadata fields:
Capture device
Capture details
Validation key
Resolution
Color Depth
Color management
Metadata harvesting
Contentdm is compliant with OAI-PMH (Open Archives Initiative Protocol for Metadata Harvesting), which is an emerging standard for metadata harvesting. Contentdm supports collection-level OAI harvesting. Our collections are harvested by the CIC metadata portal and OAIster. For more information, see the Open Archives Initiative web page at http://www.openarchives.org
