The Aggregation class - handled through ore:Aggregation - refers to ‘the set of related resources in the Europeana system about one particular provided object from one provider. These are either created by the provider or generated from the metadata by the Europeana system’.
This class acts as the One Ring in The Lord of the Rings novels, since it has the responsibility of ruling several elements.
The Aggregation class is responsible for linking edm:ProvidedCHO with its related edm:WebResource(s) and its edm:isShownAt - the data provider’s website. Most of the time, that’s the institution in charge of the item, and consequently the producer of this data.
It also holds wider information, such as the licence applied to the record, or the name of its provider and data provider. Such data is critical for consistent Europeana search results when it comes to institutions’ findability and visibility.
Part 1 - Content strategy, or how to use isShownAt / isShowBy / object
Preparing data for publishing EDM records is not always straightforward. One has first to understand the celestial mechanics of Linked Open Data through the RDF standard, and then it is necessary to map the available data to the relevant EDM field.
Working on this day in, day out, has made us aware that some of the most important fields are sometimes unclear in what they refer to. So, here is a summary of the three elements linking to the actual media, embedded into the ore:Aggregation class:
- edm:isShownAt refers to the web view of the record in full information context, on the original institution's website
- edm:isShownBy refers to the main representation of the record (if present, this will be used to generate our thumbnail)
- edm:object refers to the thumbnail image of the record (min 0.1 megapixel in size; this may be the same URL as edm:isShownBy)
You must use either edm:isShownAt or edm:isShownBy. The use of edm:isShownBy is preferred, as it would ensure a direct representation of the record in Europeana Collections. The resource in edm:object is displayed in our search results list/grid, as a thumbnail for a specific record. Then, once on the Europeana individual record page, the user will see the resource in edm:isShownBy and will be pointed to the edm:isShownAt resource if they click on the ‘View at’ link (top right side).
Part 2 - Institutions’ visibility, or demystifying the Provider, Intermediate Provider & Data Provider roles
We, at Europeana, love to classify things. It is not only a compulsive behaviour, but it helps us to ensure we can provide the most filterable search results for our users. Therefore, three categories were created in order to define our partners:
- edm:DataProvider (mandatory) refers to the institution in charge of the cultural object and which has created the related data;
- edm:IntermediateProvider is the intermediate organization that selects, collates, or curates data from a data provider, and which then passes the data to an aggregator from which Europeana harvests;
- edm:Provider (mandatory) is the organization providing data directly to Europeana;
Example: In the case of the data provider Zuidwestbrabants Museum, which delivers data through Erfgoedplus.be to LoCloud, the properties would look like this:
Accross a dataset these labels need to be identical (no variant spellings for the same institution) to ensure the consistency of the information displayed and queryable through our search engine.