Posts Tagged ‘OAI-PMH’

My explorations of federated collections available via OAI-PMH led me to three sites I liked. I should be more critical, perhaps; there are small notes of negativity below. But overall, I am impressed with many projects, even distracted by them, blinded by the science and beauty of what has already been achieved in these, The Early Days.

Gatherings of unlike things are still gatherings of unlike things, and until voice recognition and 3D rendering are incorporated and linked, and even then, we are going to travel step-wise, not immediately, to the Thing we want. These federations all act slightly differently as repositories, meaning they offer up metadata, to greater and lesser degrees, and the thing itself, to greater and lesser degrees, and related information, to greater and lesser degrees. They “own” their holdings at different depths. I discovered I could have spent a very very long time as I discovered more angles to analyze. Time drives on.

The features I look for in a good federation include: the ability to build a good and useful search across (large) collections; the ability to sort or refine search results; multiple paths into collections via guides and indexes; clarity about sources; and some kind of quantification of the resources available in specific areas (know how much you’re in for). As well as the clearest home page in the galaxy.

The three I reviewed all scored well with me, and here they are:

Digital Library for Earth System Education (DLESE)

Funded originally by the National Science Foundation. Contributors include NASA as well as educators; resources are suggested as well as directly contributed by creators. Good FAQ. Nice graphic representation of quantity available for each subject area covered. All resources are categorized by grade level. Unfortunately search results for simple searches are presented in unknown order in nearly full-record form, so scrolling is very necessary until you add facets or additional terms to cut down the hits list. Search is available by resource type, very useful, including by subtype of classroom activity. Excellent ability to build a useful set of results. Includes ability to select reviewed sources. The home page is frankly confusing, being a small jumble of radio buttons, links, text boxes, and drop-down lists smooshed against the left margin–but there isn’t so much that it can’t be figured out. It isn’t DSpace or another recognizable repository. Not my favorite, not well-designed enough, but nice content for educators.

Western Waters Digital Library

Originally funded by IMLS, now representing collections of 32 universities. Includes mission statement and collection policy, as well as a collection guide and very nice interactive collection guide map organized by river basins, unfinished but nonetheless interesting. Results of searches link out to owning repositories, so only core Dublin Core is offered within the WWDL. Thumbnails are offered where they can be, but that’s all you get within WWDL–full images only at home repositories. The home page is clean, with slideshow images.


(While not listed on either of our lists of service providers, my background checking shows that its contributions are required to be OAI-PMH-friendly, and its parent, CDL, is harvestable.) A “free public gateway to a world of primary sources” and a project of the California Digital Library, this repository offers collections targeting educators, including “themed” by era. With a browsable subject index, keyword searches show results grouped by type, and hits are shown in context for textual results. There is no advanced search; one is invited to search within a given set of results. Within Calisphere full Dublin Core is offered; linking out to the owning repository is the last and least option. Its entry page is beautiful, well laid out with a few choice chosen images representing its breadth.

I found myself taking WWDL and Calisphere head to head and tried to find the same item in both collections to compare apples and apples and came quite close. The downside of leaving WWDL immediately upon clicking on a thumbnail is leaving your result set behind; the downside of Calisphere could be seen as losing context by not easily getting to items in their native repository. I can’t tell which might be the larger federation, and they both may grow daily or at least weekly (I’d bet on it with Calisphere, unsure about WWDL). Large sets of data are good; they’re all in one place, and you can scan-search them all. On the other hand, fineness of searching has to give in at some point with huge federations; they just can’t spend the resources to offer the level of detail that a more focused collection can. They probably cannot govern their contributors to the same fine degree, either, so scattered detail in, scattered detail out.

Calisphere wins by a nose.

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