|Data Definitions Version 1.05||Go to bottom.|
Associated File: Identifies the type and name of a file containing additional information needed to view an SGML encoded digital object or to play a RealAudio digital object. This attribute is repeatable and may identify a group of files such as an SGML packet of files or an individual file such as an SGML entity file.
Associated File Name: Part of combination attribute Associated File. Identifies a file needed to view an SGML encoded digital object or to play a RealAudio digital object.
Associated File Type: Part of combination attribute Associated File. Indicates the purpose, or function of a specified RealAudio or SGML related file. Associated file types include:
Bit Depth: Indicates the number of different colors or shades of gray that can be stored in each pixel of a scanned (i.e., raster) image. Sometimes referred to as "Color Depth." Usually expressed as number of bits per pixel.
Currently recognized bit depths and the number of colors or gray tones associated with them are listed below.
Bit Depth Associated Colors / Gray Tones 1-bit Black and white only; no shades of gray 4-bit 16 colors or gray tones 8-bit 256 color or gray tones 24-bit 16.7 million color or gray tones 32-bit 16.7 million color or gray tones and 8-bits of special effects
Color Mode: Indicates whether colors or shades of gray are associated with the Bit Depth of a scanned (i.e., raster) image. Currently recognized color modes are listed below:
Color Mode Meaning Bit Depth(s) Bitonal Black and white only; no shades of gray. 1-bit Color Color tones; no shades of gray. 4-bit
Grayscale Shades of gray; no color tones. 8-bit
Creation Information: Provides information about the creation of data element content associated with a digital object. Includes creation date, indication of any special equipment used, and identification of the vendor or LC unit that created the digitized content.
Creation Date: Date that a piece of Library of Congress collection material was processed to produce a digital object destined for the inclusion in the Repository. Expressed in YYYYMMDD format. Date Created is part of the combination attribute Creation Information.
Creator: Identifies the organization responsible for processing a piece of collection material to produce a digital object destined for the inclusion in the Repository. Such organizations may be either LC work units or commercial vendors. Creator is part of the combination attribute Creation Information.
Data Element Content: The actual data carried in a digital object. Example: the actual image of a page or photograph.
Data Element Deposit Information: Indicates the date and time that a data element was added to a digital object in the Repository.
Data Element Description: Briefly identifies the nature of the content carried in a data element. If this attribute is not present, the data element inherits the description found in its associated digital object.
Data Element Relationship Information: Indicates the relationship between data elements of the same digital object. Such relationships include: ordinal ordering of sibling data elements in a presentation sequence (e.g., 1 of 26) and whole part relationships (e.g., grid coordinates; details).Note that Data Element Relationship Information is repeatable as long as the data element relationship types to be specified do not include "Stand Alone." Note also that while there can be more than one occurrence of Data Element Relationship Information in a data element, no more than one of each data element relationship type can be specified.
Data Element Relationship Type: Part of the combination attribute Data Element Relationship Information. Indicates the nature of the relationship between data elements of the same digital object. Such relationships include:
Since whole/part relationships take a variety of forms, this relationship type is further broken down into the following subtypes:
Data Element Relationship Value: Part of the combination attribute Data Element Relationship Information. Provides relationship information needed to present data elements of a digital object for printing or display. Information will vary according to the Data Element Relationship Type specified.
|Relationship Value||Relationship Type|
|Sequence number, followed by a colon and the |
total number of data elements in the sequence.
|Grid coordinates; column:row (example: a:5)||Alpha-Numeric Grid|
|Detail number (example: x01)||Detail|
NOTE: Values for "Presentation Sequence" and "Stand Alone" can be clearly expressed but values for "Part of Whole" cannot. This is because the "Part of Whole" Data Element Relationship Type covers a wider variety of conditions than originally thought. "Part of Whole" will need additional analysis and clarification. (02/27/97)
Data Element Rights and Permissions: Indicates, at a summary level, any limitations on the use to which the content of a data element can be put and the rationale for those limitations. If this attribute is not present, the data element inherits the rights and persmissions indicated in its associated digital object.
Data Element Use: Indicates how the content of a data element within a digital object is used. Data element uses defined to date (04/97) include:
|Data Element Use||Meaning|
|Pointer||Points to another, subordinate digital object (e.g., handle).|
|Archival||Data element contains the richest, most complete representation of the data content that is available.|
|Service||Data element contains data content that is used to respond to, or service, user requests for data presentation (e.g., display, or printing). Such data content usually is less than archival but greater than preview in its level of completeness and quality.|
|Preview||Data element contains data content that is used to provide a summary presentation of the data. Such data content usually is the smallest, shortest, briefest representation of the data that is available. Data content that is used for preview purposes includes thumbnail images, film clips, and sound bites.|
Data Size: The length of the content portion of a data element. Expressed in number of bytes.
Data Size Unit: Identifies the unit of measure used to express the length of the content portion of a data element.
|Code||Data Size Unit|
Data Type: Indicates the nature of the data found in the content portion of a data element. If applicable, Data Type is expressed as MIME type. Examples of data types identified to date (04/97) include:
|ASCII (Encoded Text)||txt|
|HTML (Encoded Text)||html|
|SGML (Encoded Text)||sgml|
|AVI (Moving Images)||avi|
|MPEG (Moving Images)||mpg|
|PDF (Encoded Text)|
|QuickTime (Moving Images)||mov|
|Real Audio (Sound)||ra|
|Real Media (Motion Video + Sound)||rm|
|Real Media (Sound only)||rms|
|Real Media (Motion Video only)||rmv|
|XML (Encoded Text)||xml|
|ZIP (Compressed Data)||zip|
Date Data Element Deposited: Date upon which a data element was added to a digital object in the Repository. Expressed in YYYYMMDD format. Part of combination attribute Data Element Deposit Information.
Date Data Element Last Revised: Indicates the date upon which a data element of a digital object was last updated or changed. Expressed in YYYYMMDD format. Part of data element combination attribute Last Data Element Revision. Default is the same date as found in Date Data Element Deposited.
Date Deposited: Date upon which a digital object was added to the Repository. Expressed in YYYYMMDD format. Part of combination attribute Deposit Information.
Date Last Revised: Indicates the date upon which a digital object was last updated or changed. Expressed in YYYYMMDD format. Part of combination attribute Last Revision. Default is the same date as found in Date Deposited.
Deposit Information: Indicates the date and time that a digital object was added to the Repository.
Description: Briefly identifies the nature of the digital object. For example, "amrlg" indicates a compilation of photos from the 'Coolidge and the Consumer 1920-1930' compilation.
Digital Object Use: Indicates the functional nature of a digital object. They include:
Equipment: Identifies any special equipment used to produce a digital object destined for the inclusion in the Repository (e.g., scanner). Equipment is part of the combination attribute Creation Information.
Extent Information: Indicates the range over which a digital object reaches as expressed in space or time. Digital object extent types include pixel dimensions, such as for a scanned image, and duration, such as the playing time of an audio recording or motion picture. Extent Information is a combination attribute with two subordinate attributes, extent type and extent value.
Extent Type: Part of the combination attribute Extent. Indicates whether the extent is a range of space or time and the nature of how it is expressed. Extent types currently defined are listed below.
Extent Value: Part of the combination attribute Extent Information. Provides measurement values used to indicate the dimensions or playing time of a digital object. Extent Value will vary according to the Extent Type specified. Value formats for currently defined Extent Types are indicated below.
(W = width and H = height)
(H = hours, M = minutes,
Handle: A sequence of lower case alphanumeric characters that uniquely identifies a digital object; the persistent global identifier of a digital object. A handle contains a Naming Authority designation, followed by a slash (/), followed by a Unique String identifying the individual digitized object. Example: loc.ndlp/amrlp.3a16116.1
The Naming Authority Designation consists of a high level Naming Authority designation (e.g., "loc") followed by a period (.) and a Lower Level Naming Authority designation (e.g., "ndlp"). For the list of currently recognized Name Authority designations associated with LC, click here.
The Unique String portion of the Handle consists of an aggregate name followed by the name of a metaobject within the aggregate and then the Local Name Convention for the individual digital object being identified. Single periods (.) are used to separate these Unique String components.
Note that aggregate names are often found in MARC field 856, subfield d or its equivalent. Note also that while the Unique String may be assigned based on how the digital object was produced, it operates as a nonsemantic identifier.
The Local Name Convention for an individual digital object is analogous to "file ID" in the current (mid-1996) naming schema for Coolidge Compilation digital objects.
For a description of how handles would appear in external pointers such as MARC records, HREFs, or EADs, see External Pointers to Digital Objects.
Instance: Identifies the version of a digital object with which a data element is associated. The data element may contain either a pointer to another digital object or actual object data (e.g., an actual image or part of an image). An instance may be comprised of more than one of a digital object's data elments.
Last Data Element Revision: Indicates the date and time that a data element of a digital object in the Repository was last updated or changed.
Last Revision: Indicates the date and time that a digital object in the Repository was last updated or changed.
Number of Data Elements: The number of data elements used to relate digital objects to a metaobject.
Number of Instances: Indicates the number of versions of a digital object that are represented by the data elmenets associated with that object.
Original Content Type: Indicates the general physical nature of the original collection item from which a portion of digitized content was produced. The purpose of the Original Content Type attribute is to facilitate digital object presentation. Original Content Type does not indicate how the digital object was produced (e.g., scanned, encoded), nor does it indicate the genre or subject content of the digital object. Original content types include:
[Note: Only digital objects having Digital Object Use set to either Content Digital Object or Hybrid Digital Object will have their Original Content Type attribute set to anything other than "None."]
Orientation: Indicates how a scanned image is arranged relative to where the top of the image would normally be positioned.
Value Meaning 000 Top of scan is properly oriented. 090 Top of image is 90 degrees clockwise from where it should be. 180 Top of image is 180 degrees clockwise from where it should be. 270 Top of image is 270 degrees clockwise from where it should be.
Owner of Digital Object: Identifies the institution or individual who owns a digital object. The default for owner of digital objects in the repository is "Library of Congress."
Page Information: Provides information about a special function or characteristic of a data element associated with scanned, non-motion visual content; in particular, text and raster maps.
Part of combination attribute Page Information.
Indicates a special function or characteristic of a data element
associated with text content. Page types include:
Page Value: Part of combination attribute Page Information. Provides data values associated with specified page types. Examples of page values include:
|Page Value||Page Type|
|Table of Contents||Feature|
|ix||Print Page Number|
|78||Print Page Number|
Parent Object Information: Identifies any parent object(s) with which the digital object is directly/immediately associated.
Resolution: Indicates the quality or sharpness of a scanned or printed image. Expressed as the number of dots-per-inch (dpi).
Rights and Permissions: Indicates, at a summary level, any limitations on the use to which a digital object can be put and the rationale for those limitations. Rights / permissions include:
For the full list of currently recognized rights and permissions, click here.
Special Function: Identifies a role played by a digital object in addition to the use specified in the Data Element Use attribute. Currently defined Special Functions are listed below:
Since a digital object may perform more than one special function, the following combinations of digital object special functions are recognized:
|Combination||Special Functions in Combination|
|01||Preservation Master, Migration Master, and Best Copy|
|02||Preservation Master and Migration Master|
|03||Preservation Master and Best Copy|
|04||Migration Master and Best Copy|
Time Data Element Deposited: Time of day at which a data element was added to a digital object in the Repository. Expressed in HHMMSS.SS format. Part of combination attribute Data Element Deposit Information.
Time Data Element Last Revised: Indicates the time of day at which a data element of a digital object was last updated or changed. Expressed in HHMMSS.SS format. Part of data element combination attribute Last Data Element Revision. Default is the same time as found in Time Data Element Deposited.
Time Deposited: Time of day at which a digital object was added to the Repository. Expressed in HHMMSS.SS format. Part of combination attribute Deposit Information.
Time Last Revised: Indicates the time of day at which a digital object was last updated or changed. Expressed in HHMMSS.SS format. Part of combination attribute Last Revision. Default is the same time as found in Time Deposited.
|Created: 3/15/97 Revised: 4/29/99|
|Library of Congress - Digital Repository Development & Support|