Open Linking and the OpenURL Standard Eric F. Van de Velde, Ph.D. Chair, NISO Committee AX Director of Library Information Technology California Institute of Technology Harry E. Samuels Member, NISO Committee AX Digital Library Projects Coordinator Endeavor Information Systems

What Is NISO Committee AX? A NISO standards committee developing a standard for the OpenURL Charge of committee “… Standards Committee AX is charged with developing syntax for creating web-transportable packages of metadata and/or identifiers about an information object...” Complete statement of charge is at NISO web site at Committee web site is at

What Is Linking? By linking, we typically mean linking (through the web) From some source that can provide metadata To some target that relates to the source

Linking Has Been Around But linking has been controlled by the source We call this closed linking There’s nothing wrong with closed linking, but it does have shortcomings

Shortcomings of Closed Linking Typically, sources know little of the user’s context or what the user has access to They may be static and lack persistence Most importantly, the source determines the destinations of the links

What Is Open Linking? Open linking introduces a new component into the linking process The Link Resolver

What Does The Link Resolver Do? A link resolver accepts metadata from a source and presents links based on logic and business rules administered locally It puts link resolution into the hands of the institution (library) It knows the user’s context and what the user has access to

SourceLink Resolver Metadata Target Link What Does Open Linking Look Like? Target Link

What Can the Link Resolver Provide Links To? Full-text articles - Very powerful tool when source is an article citation Extended Services Document delivery request Inter-library loan request Initiate a search on an internet search engine based on the received metadata Initiate a search of the local OPAC (on-line public catalog) based on the received metadata Any service for which a URL can be constructed

Source Link Resolver Metadata Target Document Delivery What Does Open Linking Look Like? Target OPAC Search Full Text

What Is An OpenURL? An OpenURL is a transportable metadata package Typically transported over the web using an HTTP GET or HTTP POST

Source Link Resolver Metadata Target Document Delivery What Does Open Linking Look Like? Target OPAC Search Full Text OpenURL standardizes this part of the communication

Source Link Resolver OpenURL Target Document Delivery What Does Open Linking Look Like? Target OPAC Search Full Text

What Does an OpenURL Look Like? &date=1998&volume=12&issue=2&spage=134 What Does It Mean? serv.uni.edu = base URL of link resolver issn = Publication date = 1998 Volume = 12 Issue = 2 Starting Page = 134 Metadata infers that this is metadata for a journal article

OpenURL Also Supports Identifiers? What Does This Mean? serv.uni.edu = base URL of link resolver Digital Object Identifier = 123/3456

In summary... Linking takes the user from one information resource to a related information resource (via the web) Open Linking utilizes a link resolver to select and present links to appropriate related information resources independent of the original information resource

In summary... A link resolver requires a package of metadata to determine links to appropriate information resources OpenURL standardizes the syntax for transmitting a package of metadata to a link resolver

In summary... NISO Committee AX is a NISO standards committee developing a standard for the OpenURL