<dao> Digital Archival Object

<dao> is a linking element that uses the attributes ENTITYHREF or HREF to connect the archival finding aid information to electronic representations of the described materials. This allows the content of an archival collection or record group to be included in the finding aid. These may include images (graphics or scanned text), a/v clips, and transcriptions of text. It may be used for everything from examples to digital surrogates for an entire collection. If linking to electronic objects that are not a part of the described materials, use <extptr>.

Use the Extended Pointer <extptr> element to link the finding aid to electronic objects that are not part of the described materials. Related and useful elements are: <daodesc>, <daogrp>, and <daoloc>.

<dao> is one of the elements which may be used within <archdesc>, <archdescgrp>, <c>, <c01> through <c12>,<descgrp>, <did>, <odd>, and <scopecontent>.


  • ALTRENDER – not required. Use if the content of the element should be displayed or printed differently than the rendering established in a style sheet for other occurrences of the element.
  • AUDIENCE – not required. Use to set whether the element’s contents will be visible to external users or to internal ones. Possible values are: “internal” and “external.”
  • ID – not required. Creates an ID for element. Can be used for linking.
  • ACTUATE – not required. Designates whether object is displayed automatically or if requested. Values may be: onload, onrequest, actuateother, or actuatenone.
  • ARCROLE – not required. URI preference that identifies a resource that describes some property of an arc-type or simple-type linking element.
  • ENTITYREF – not required. The name of a nonparsed entity declared in the declaration subset of the document that points to a machine-readable version of the cited reference.
  • HREF – not required. The locator for a remote resource in a simple or extended link. Takes the form of a URI unless the locator is within the document that contains the linking element.
  • LINKTYPE – FIXED. Must contain the value “simple.”
  • ROLE – not required. Information that explains to application software the part that a remote resource plays in a link.
  • SHOW – not required. Defines whether a remote resource appears at the point of the link, in a new window, or replaces the link. Optional values are: new, replace, embed, showother, or shownone.
  • TITLE – not required. Information that serves as a viewable caption which explains to users the part that a resource plays in a link.
  • XPOINTER – not required. The locator for a remote resource. The XPOINTER attribute takes the form of a Uniform Resource Identifier plus a reference, formulated in XPOINTER syntax, to a sub-resource of the remote resource. XPOINTER enables linking to specific sections of a document that are relative, i.e., based on their position in the document or their content, rather than by reference to a specific identifier such as an ID.


<dao> may contain the <daodesc> element, which is used to encode further information about the <dao> element.


This simple example is taken from the LoC tag library:

<c level="file">
			<unitdate type="inclusive" normal="1895/1928">1895-1928</unitdate>
	<c level="item">
			<unittitle>John Smith graduation portrait</unittitle>
			<unitdate type="single" normal="18950528">May 28, 1895</unitdate>
			<dao linktype="simple" href="http://imgs.ud.edu/archives/image/f12001_1.jpg"
				actuate="onrequest" show="new"/>
	<c level="item">
			<unittitle>Photographs of John Smith and family members</unittitle>
			<unitdate type="inclusive" normal="1907-1928">1907-1928</unitdate>
			<physdesc><extent>12 photographic prints</extent></physdesc>

EAD tag library entry for <dao>.