University Libraries Metadata Core
The University Libraries' metadata-sharing project is based on the concept that large numbers of distributed digital collections can continue to exist as separately maintained resources, but their discovery and use can be maximized by aggregating through one search interface common descriptive information about each digital image, text database, or other object. A central search gateway that includes a core set of information about every object in every collection across campus dramatically increases the odds of discovery, and use of such assets.
Furthermore, many potential creators of digital collections may not be able to expend the necessary resources to build and maintain an online database. The University Libraries' system architecture also permits data for individual projects to be stored centrally, but retrieved by users in a transparent manner that, from their perspective, appears to be a separately owned and operated project site. This is accomplished by assigning different XSLT stylesheets (directory of stylesheets) to each digital collection. If a user searches through the common union database interface, the stylesheets employed are different than if the user searched one digital collection through its own search page on the Internet.
The following list of elements is the common core of descriptors stored and searchable in the Digital Collections database. These data elements are formally established in an XML-based Document Type Definition named images.dtd. A crosswalk between our core metadata standard and other common metadata standards is also available.
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| digitalid |
Max length is 128 characters. Must occur only once per record. A unique identifying character string for each digital object. Typically, an identifier such as "photo1, photo2, etc." is inadequate for managing large groups of digital files, so choose an identifying scheme carefully. This element is REQUIRED, and must be a part of the dataset contributed to IMAGES from pre-existing databases.
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| standardid |
Max length is 32 characters. May occur zero, one, or multiple times in a record. If an object (original or digital) is commonly referred to by a standard identifying number or character string, this information may be included in the standardid element. This element is OPTIONAL.
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| title |
Max length is 255 characters. This element is repeatable, so that multiple versions of a title (including foreign language versions) may be entered for a digital object. It may occur, zero, one, or multiple times. The title element is generally reserved for titles that are formally or commonly assigned to an object. This element is OPTIONAL.
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| series |
Max length is 128 characters. Must occur only once per record. For large groups of digital objects, intellectual groupings are desirable to permit more precise searching and retrieval. For example, a large group of images on India might be grouped into sub-categories such as "India -- Buildings", "India -- Clothing", an so forth. This element is REQUIRED. The series element is divided into 2 parts: level1 should be the same highest-level grouping for ALL images in a digital collection and level2 permits the content owner to add a secondary level of subgrouping. Additional sublevels of grouping beyond level2 are possible, please consult with the IMAGES project manager for further information. If no groupings or sub-groupings are provided, one overarching series value will be added to each object record submitted.
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| caption |
Max length is 4,000 characters, but recommended length is 255 characters. This element may occur only zero or one time. Many digital objects, particularly visual resources such as photographs, may not have a formally assigned title, but do have a descriptive caption that is akin to title information. The caption element is OPTIONAL.
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| annotations |
Max length is 4,000 characters, but recommended length is 255 characters. This element may occur only zero or one time. Hand-written notes or annotations on an object should be included in the annotations element. This element is OPTIONAL.
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| creator |
Max length is 128 characters. This element may occur zero, one, or multiple times. Each person or corporate body with PRIMARY responsibility for the creation of an object or its content should be entered into a separate creator element. All personal or corporate names should be entered in the format recommended by the Anglo-American Cataloging Rules. If an entry for a person or corporate body has already been established within the library community (hint: searching in library online catalogs is a good place to start), the established form of this name should be entered. This element is OPTIONAL.
EXAMPLES:
Smith, J. D. (James David), 1850-1900 (only use dates if already in an established heading, or if you're absolutely certain)
Smith, James D., 1850-1900
American Industrial Systems Machinery, Inc.
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| contributor |
Max length is 128 characters. This element may occur, zero, one, or multiple times. Each person or corporate body with SECONDARY responsibility for creating an object or its content should be entered into a separate contributor element. All personal or corporate names should be entered in the same format as recommended for the creator element. This element is OPTIONAL.
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| published |
Max length is 255 characters. If a digital or original object has been published, publication information may be entered in this element. This element is OPTIONAL.
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| imageyear |
Max length is 32 characters. This element may occur only zero or one time. The imageyear element is intended to record the date of an object's original creation (if a digital copy was made of a physical original, this element is for the creation year of the original item).
The imageyear data field is the most complicated in the entire IMAGES data structure, so that we can support sorting, display, and other sophisticated date functions. In its most simple form, the imageyear field can contain ANY text string, if contributors do not wish their content to be date searchable or sortable.
In most instances, however, we anticipate that contributors will prefer to take advantage of the fullest date searching and sorting capabilities. To do so, the IMAGES database requires:
Display date value: A display-only value for the imageyear.
Type: Indicate whether the date is a single year or a year span.
Certainty: Is the date an "exact" date or an approximate ("circa") date?
Normalized date: To aid in computer sorting, the two four-character year value for a date span should be entered as "1940/1950". If either/both of the year values are BC or BCE, a negative sign (-) should accompany each date. Using these guidelines, "-0400/0300" would signify that an image was created somewhere between 400 BCE and 300 AD. For single date values, the year should be preceded by the "/" to assist in computer handling of the date. The year 1948 would be entered as "/1948".
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| imageperiod |
Max length is 64 characters. This field may occur zero, one, or multiple times. Often, the ability to sort or browse by more general date spans (such as by decade or named historical epoch) is useful. The imageperiod element may contain period entries by decade for the 19th, 20th and 21st centuries (in the form, "1920s", "1930s", etc.), or generally accepted names for historical spans for any period. When entering names for historical periods, authoritative names for these eras are recommended. Remember to enter terms for the same period consistently, to aid in consistent and reliable retrieval. This element is OPTIONAL.
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| holding |
Max length is 255 characters. This element may occur zero or one time. The name of the current owning repository for the original object may be recorded in the holding element. For entries on past ownership, see the provenance element. This element is OPTIONAL, but recommended if such information is available.
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| objectlocation |
Max length is 255 character. This element may occur zero or one time. The objectlocation element may hold storage information for the original object, such as shelf location, call number, etc. Do not record information in this element about the location of digital copies. This element is OPTIONAL, and its display may be suppressed.
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| provenance |
Max length is 255 characters. This element may occur zero or one time. Information such as the creation and ownership history may be recorded in the provenance element. This element is OPTIONAL.
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| medium |
Max length is 32 characters. This element may occur zero, one, or multiple times. If an object can be grouped into a broad genre or category of visual works (examples include "Photograph", "Poster", "Architecture", "Illustration", etc.) such information should be included in the medium element. A full list of acceptable genre terms currently is under development. This element is OPTIONAL.
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| media |
Max length is 64 characters. This element may occur zero, one, or multiple times. Specific materials or formats used to create an original object may be recorded in the media element. This element may contain a wide variety of descriptive information. This element is OPTIONAL.
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| dimensions |
Max length is 128 characters. This element may occur zero or one time. The dimensions element may contain information on the physical dimensions of an original object, or the total number of component units. This element may eventually be genericized to a label such as to incorporate descriptions such as total pagination, box counts, etc. This element is OPTIONAL
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| description |
Max length is 4,000 characters, but recommended length is 255 characters. This element may occur zero or one time. Any descriptive about an object or its content may be entered in the description element. Preferably, however, information on dimensions, for example, will be entered into the element, intended for greater specificity in searching and retrieval. The description element is intended for types of description not accommodated by other elements. General notes, however, may be entered into the note element. This element is OPTIONAL.
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| subject |
Max length is 255 characters. This element may occur zero, one, or multiple times. The element is intended to contain one term or subject heading per element. It is highly recommended that all keyword terms be selected from controlled vocabularies such as the Art and Architecture Thesaurus, Library of Congress Subject Headings, Thesaurus for Graphic Materials, or controlled descriptive vocabularies for specific disciplines. This element is OPTIONAL.
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| userights |
Max length is 255 characters. This element may occur zero or one time, but it is strongly recommended that participants include some statement of acceptable uses and copyright status of digital objects. This element is OPTIONAL.
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| note |
Max length is 4,000 characters, but recommended length is 255 characters. This element may occur zero or one time. The element may contain general notes or useful information that is not suitable for other elements. This element is OPTIONAL.
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| internalnote |
Max length is 255 characters. This element may occur zero or one time. Useful information that should generally not be displayed to the public may be entered in the internalnote element. This element is OPTIONAL.
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| language |
Max length is 3 characters. This element may occur zero or multiple times. A 3-letter code indicating primary language of the digital object, if appropriate. This element is OPTIONAL.
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| thumbnail_image |
The following OPTIONAL elements are used to record specific information about a thumbnail version of an image:
thumbpath = an absolute URL path to the location of the thumbnail image
thumbformat = the MIME type (usually "image/jpeg")
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| reference_image |
The following OPTIONAL elements are used to record specific information about a reference (screen-sized) version of an image:
referencepath = an absolute URL path to the location of the reference image
referenceformat = the MIME type (usually "image/jpeg")
referencesize = file size in Kb of the digital file
referenceres = resolution of the reference image
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| master_image |
The following OPTIONAL elements are used to record specific information about a high resolution version of an image:
masterpath = an absolute URL path to the location of the master image (usually not used)
masterformat = the MIME type (usually "image/tiff")
mastersize = file size in Mb of the digital file
masterres = resolution of the hi-res image
masterloc = Free-textual statement of how to obtain a copy of the master image.
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| relatedurx |
Max length is 128 characters. This element may occur zero or multiple times. The only type of information permitted in this field are URL's, URI's, PURL's, etc., which link to a related resource. However, the element also has a "relation" attribute that allows the content owner to specify the nature of the relationship between the image being described, and the referenced URL, URI, etc. Specific valiues for the "relation=" attribute include: Unspecified [default], IsPartOf, IsVersionOf, and IsFormatOf.Current recommended practice is to record the home site URL of a distributed database to which a digital object belongs. For example, if the object belongs to a database of Indian art, the relatedurx might contain the URL for the database's home page, and a relation="IsPartOf". This element is OPTIONAL.
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| datestamp |
When image records are first loaded into the IMAGES database, or subsequently altered, the metadata record is datestamped for versioning control. If this OPTIONAL field is not present, it is automatically added by the IMAGES system. If you have specific version control needs, please contact the IMAGES project manager for consultation.
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