OpenURL and context-sensitive linking: putting libraries back in the driver's seat
IngentaConnect is OpenURL compliant. We've launched a new OpenURL alerting service. In this issue of eyetoeye alone, there are enough references to OpenURL to hint that it's a hot topic. Trouble is – like so many hot topics – it can leave many of us scratching our heads and wondering exactly what all the fuss is about. If that's you, read on and we'll try to fill in the gaps.What is an OpenURL?
The OpenURL is a standardised linking syntax used to carry metadata about an object. In our case, the object is most likely to be an article, and the metadata is likely to include citation information such as the title of the journal containing the article, the relevant volume/issue/page numbers – as much information as is available. OpenURLs are usually constructed by a source, in order to query a link server.
So, what's a link server?
A link server, sometimes referred to as an OpenURL resolver, is a software package which has nominated known resources for resolving OpenURL queries. Libraries which have enabled a link server can choose which resources they want to offer to their users, including local holdings. So, the link server is basically the middleman – firstly it gets asked (via an OpenURL query) what it knows about a given article, secondly it checks its holdings database (often called a knowledge base) to see what resources it has available for that article, and thirdly it displays these resources to the user along with links to each target.
I think I'm with you. But what's the point?
Normally, a source (e.g., the active references in Ingenta's full text PDFs) will only be able to provide hard-coded links to resources it knows about. So. an article cited within an Ingenta PDF will only be linked to one of Ingenta's reference linking partners – perhaps via CrossRef to the publisher-hosted full text, or to an abstract database such as Medline or CSA. Whilst such onward links are undoubtedly useful, there are two obvious problems.
Firstly, the process of adding active links behind a given citation is controlled by the source, which can only add a link when it knows of a location for the cited article – and since the source cannot know about all the places the article exists (for example, in the user's institution's print collection!), there will be instances where a citation does not offer any onward links – even if the library might have been able to provide access to the cited article. This is the "dead end" problem, in that the user's research path is cut off by lack of onward links.
Secondly, since the source can only add in links to targets it knows, the links it does add might direct users to resources they are not licensed to access. They might just give up at this point (hitting another dead end in the process), but equally they might pay to view content which they are actually entitled to access freely elsewhere. This is known as the "appropriate copy" problem.
The point of link servers, therefore, is to remove the control (or perhaps, the burden) of implementing links from the source, and pass it to the user's library. The library knows what resources its users are entitled to access, and can configure the knowledge base in its link server to know about these – local holdings, licensed database packages, online subscriptions, preferred document delivery suppliers or ILL. The source is only required to tell the library what article the current user wants, and the link server can then be responsible for offering "context-sensitive" links to the user – i.e., links which take into account who the user is, what institution they are affiliated to, and what access rights they therefore have, to both online and offline content. Ultimately, the OpenURL (in partnership with a link server) enables more effective, and more efficient, collection management.
It does sound pretty complicated. What's required to get it all to work?
Sources, such as Ingenta, need to be able to hold information about an institution's link server (at minimum, the link server's base URL) in its profile of that institution. In addition, sources need to have a linking system dynamic enough to recognise that the current user comes from an institution with a link server, and to render different links for different users as a result. When it recognises that a link server is active, the source needs to create an OpenURL by taking the link server's base URL, and adding the available metadata in a standard format (the OpenURL syntax).
Link servers, of which the most well-known is Ex Libris' SFX, need to contain a knowledge base, which consists of (a) a holdings database of that library's known resources (or targets – journals to which it has access, with coverage information for each) and (b) the appropriate syntax for linking to each of those targets.
Targets need to have a predictable linking syntax, so that a link server can automatically create a link to the target based on the information it has received from the source (via the OpenURL link).
Right. So I've got a link server. How do I integrate it with IngentaConnect?
You can add details about your link server to your IngentaConnect institutional profile, by logging in with your administrator username and password and following the link to Link server management (under Collection). Here you can enter the base URL of your link server, along with the URL of the icon image which you would like to appear next to links to your holdings. You can also enter some text to further inform your users about the link.
Once configured, OpenURL links to your link server will then appear when your users click on active reference links within IngentaConnect articles – both from HTML reference lists, and from PDF-embedded reference links. The OpenURL link will be given top billing on the list of available onward links.
If your institution is signed up for one of Ingenta's alerting services, you can also upgrade to include OpenURL links in alert emails – read about the launch of this service elsewhere in this issue.
OK. That's enough for now. But where can I find out more?
The Library of Congress has put together a useful page listing link server products and vendors.
There are numerous articles on the subject, ranging from non-technical overviews to more complicated specification discussions; some of these are also listed on this page of the Library of Congress site. Beginners would have most to gain from the following:
Linking Services Unleashed by Jill E. Grogg, Searcher, vol 11 no 2 (Feb 2003).
For a demonstration of OpenURL and link servers in action, see Andy Powell's excellent walkthrough:
OpenResolver: a Simple OpenURL Resolver by Andy Powell, Ariadne, Issue 28 (June 22, 2001).
For a contextual view of OpenURL within the overall linking landscape, see this article by our own Linking Manager:
After the goldrush – the golden age of reference linking by Charlie Rapple, Learned Publishing, vol 17 no 4 (Oct 2004), pp299-304.