As described in our last post, the World-Historical Gazetteer (WHG) and Pelagios projects have adopted the term “trace” to refer to historical entities for which there is spatial-temporal data of interest, including events, people, works, and other artifacts. Following the lead of Pelagios’ Peripleo, the WHG system (initial beta release July 2019) will index contributed trace data, linking them to places in an underlying knowledge graph that is a) navigable in graphical features, and b) queryable in an API.
We (WHG and Pelagios) have set out to create a standard Linked Traces data format (LTAnno), which will take the form of W3C web annotations. We welcome (need, actually) active collaboration in that modeling task, and feedback from interested observers.
An LTAnno target is an LOD web-published record of some entity, and its body contains a) a place record URI, b) a relation between the place and the target entity, and c) an optional temporal scoping for each. It should be possible to have multiple bodies per target (per example below) and multiple targets per body (e.g several people having the same birthplace, several works having the same place as subject, and so on).
A Trace Data Example
WHG will fully support LTanno format, and likely focus on a few types of trace data, including those related to geographic movement such as journeys and cultural diffusion. Figures 1 and 2 illustrate a test Journey record using the draft LTAnno format. In it, 38 annotation bodies referring to WHG place URIs are linked to a single target, the WorldCat record for the source of the waypoints, “Xuanzang: a Buddhist pilgrim on the Silk Road” (Wriggins, 1997). A user finding their way to any of the 38 places will learn they were waypoints on the journey, be able to see the others, and to navigate to their respective place pages. This only scratches the surface of what will be possible, given a growing volume of trace data for other events, people, and works.
Next Steps
The draft examples of LTAnno for different trace types are only preliminary, for discussion. In the coming weeks, Rainer Simon and I will coordinate development of a spec our respective projects can support. There is a Google Group and email list for this working geoup, and we will go into further detail about the draft spec there shortly. Active collaboration by data modelers, data providers, and future users of the format is most welcome.
One of the first orders of business is gathering a few sample datasets for different types of traces, in order to better understand the variety of modeling circumstances. These will then have to be converted into early versions of the format to test usability and usefulness.
At a later stage, we’ll have to put together a simple Linked Pasts ontology describing terms introduced by both this new LTAnno format and the recently developed Linked Places format for gazetteer data connectivity.