Corpus Nummorum integrated into Nomisma.org

At the European Coin Find Network / Nomisma.org meeting several weeks ago in Sofia, Bulgaria, I learned that Corpus Nummorum had a SPARQL endpoint. However, it is an endpoint that supports only the query protocol without a UI wrapper to make it more publicly usable. Sitting in the conference auditorium, I used the Nomisma SPARQL endpoint to execute the SERVICE protocol in order to query the CN endpoint. This revealed a triplestore that contains both types and coins, almost entirely conformant to the Nomisma.org data model (there are some variations to model bibliographic references or source collections). However, federated queries are relatively slow. Upon arriving back home, I spun up a simple SPARQL UI wrapper (which functions exactly like Nomisma), that I had originally built as an interface on top of the old defunct British Museum RDF export Matt Lincoln had squirreled away. This UI wrapper works on any SPARQL 1.1-compliant endpoint, whether it was running on my locally installed instance of Fuseki or any accessible endpoint on the web (as is the case with Corpus Nummorum).

Corpus Nummorum SPARQL results in a GUI

After exploring the type and coin data a bit further, I created two SPARQL queries that implement CONSTRUCT to generate RDF/XML exports, one for types and the other for coins. I created an XSLT identity transform to slightly modify the structure of the RDF I extracted from the endpoint so that it would validate in the Nomisma RDF import system. I also replaced the static image URLs from the Bibliothèque nationale de France and American Numismatic Society with IIIF service URIs.

Most of the coins have images, although a significant number of examples in CN are photographs of plaster casts rather than the original object. The plaster cast photographs are modeled slightly differently in the RDF than our standard model, and I did not modify my SPARQL query to acquire these image links in the data I uploaded into Nomisma. Nor, at present, have I incorporated the plaster cast photos in the model CN developed, as the SPARQL queries for displaying images in Nomisma would have to be updated (and possibly also some code).

As far as I can tell though, the die axes, weights, and diameters for the coins represented by plaster casts measure the original metallic object, and are therefore accurate numbers to use for statistical analysis.

Enhancing Research Context within Nomisma.org

Much like the recent integration of IRIS types into the Nomisma.org LOD ecosytem, the upload of more than 11,000 coin types and 28,000 specimens from Corpus Nummorum fills in a sizeable gap in the context pertaining to individual Nomisma concepts related to the coinage of Thrace and the surrounding regions of Moesia Inferior, as well as Troas and Mysia in Anatolia. Most broadly, the Nomisma ID for Thrace is augmented with a paginated list of over 10,000 coin types, many of which are illustrated by at least one specimen, ranging from Greek types from Corpus Nummorum to Roman Imperial types in OCRE.

Drilling down into narrower concepts, such as mints or authorities, reveals more refined visualizations. The Kingdom of Odrysian Thrace produced 66 types from the mid-5th to early 2nd century BC, although only about 20% are attributed to two certain mints.

The map and types of Odrysian Thrace

 

 

Some Caveats

Aside from the aforementioned lack of photographs of plaster casts, the Corpus Nummorum dataset includes some duplication of both types and coins that we should be aware about. Since the CN typology runs the gamut of coinages produced in Thrace and nearby regions throughout the duration of antiquity, there is some overlap between these types and other corpora, including Hellenistic Royal Coinages and Roman Provincial Coinage Online. CN types don't like to these other URIs, or vice versa, so queries may duplicate statistics from the same object. Similarly, since the CN database records all specimens internally rather than linking to external collections, coins from Nomisma partners that are already linked to HRC types that overlap with CN have also been duplicated in the CN export. The long-term solution here is for Nomisma partners to catalog their own collections with CN type URIs and then weed these items out of the Corpus Nummorum export. The canonical URI for a coin should be published by the holding institution rather than independent research datasets.

 

Duplicative types minted in Aenus and coins between CN and Seleucid Coins Online

There are about 500 coins from the ANS that have been given CN object URIs that are now available through Nomisma, but actually relatively few of these are duplicative of the coins the ANS has exported to Nomisma through links to HRC type URIs. However, we should incorporate CN URIs for non-Royal coinages into our own database so that we can export them directly. The same should apply for collections in Berlin's IKMK network.

Greek types from IRIS integrated into Nomisma

A few weeks ago during the Hackathon Athens at the French School, nearly 13,000 coin types from IRIS (IDs Recorded In Skeleton) were loaded into the Nomisma.org SPARQL endpoint. These types are now available alongside those published by the American Numismatic Society's Hellenistic Royal Coinages project, making it possible to query and visualize data across a broader spectrum of Greek royal and civic coinages. Although the IRIS types are not as completely detailed as those from other projects (containing obverse and reverse type descriptions and legends, material, authority, mint, region, and issue dates but notably not denominations or portraits/deities), it is still possible to list these civic coinages in the example types for authorities and mints within the Nomisma.org interface.

See for example, the URI for the Achaemenid Empire:

The Nomisma page for the Achaemenid Empire

This is an excellent illustration of a significant body of types enhancing the research context of a political entity. Previously, this map would have shown IGCH coin hoards that were linked to Achaemenid rulers, but the authorities, whether dynasts themselves or satraps issuing in the name of the dynasty are linked to both mints and the Achaemenid Empire Nomisma concept. The map now displays the geographic distribution of the production of Achaemenid coinage, centered primarily in Anatolia, but also extending into the Levant and a single issue in Babylon.

There is a list of nearly 300 total types related to this political entity, ordered chronologically and linked to IRIS. The types are downloadable as CSV directly from the Nomisma SPARQL endpoint.

Eventually, the coins from the Bibliothèque nationale de France that are linked to IRIS will be merged into the exports that have been linked into other Nomisma-affiliated projects, and examples from the BnF and other institutions that begin to catalog with IRIS URIs will begin to populate the tables on Nomisma pages to illustrate the types.

Recapping ECFN / Nomisma in Sofia and Hackathon Athens

I am finally back in the office as of yesterday following two weeks in Europe for two related conferences: the 10th joint meeting of Nomisma.org and the European Coin Find Network and Hackathon Athens, hosted by Thomas Faucher at the French School of Athens. The former meeting is increasingly a formal conference while the latter included presentations of the current state of several projects which jumped off two days of workshops and roundtable discussions. After the conclusion of the Hackathon, I helped install Numishare on a cloud server for CEAlex to publish coins from archaeological excavations in Alexandria, Egypt.

My presentation at the ECFN/Nomisma conference, "FAIR Findspots: Making Data Reusable," is about the current Nomisma.org data model for representing findspots and linking findspots to existing gazetteer URIs, such as Geonames or Wikidata. I discussed interoperability through using HTTP protocols (content negotiation) which enable external database systems to reuse hoard/findspot data for cataloging. An example that I made is the Coin Hoards of the Roman Empire project. This is one of the largest-scale numismatic datasets in existence, although hoard URIs cannot be reused for cataloging in the sense that machine-readable data cannot be extracted from CHRE in order to power geographic visualizations (in contrast to coinhoards.org). Making CHRE more reusable and interoperable would radically transform the research value of other, related projects, such as Online Coins of the Roman Empire. I am hoping with further technical guidance, the IT staff at Oxford can implement standardized data exports from the CHRE database to enhance external projects.

A PDF of my presentation is available at https://doi.org/10.5281/zenodo.8120871, and the presentation can be viewed at the 6 hour 39 minute mark of the livestream on YouTube.

In Athens, I presented a general introduction to Nomisma.org and conducted a live demo of using OpenRefine to normalize some Roman imperial coinage data from the Getty museum, demonstrating the Nomisma.org and OCRE reconciliation APIs. The intention wasn't to teach participants the ins and outs of using OpenRefine (which can't be done in 45 minutes), but to illustrate the sorts of tasks that can be semi-automated in preparing data for integration into Nomisma.org.

The demo presupposes that the coins are already online. We did discuss how to start from scratch. There's no easy answer to this; data still need to be inputted in spreadsheets or exported from excavation databases (for example, Microsoft Access or FileMaker) into CSV, normalized, and then imported into Numishare or the Dedalo platform. The coin finds of Sardinia are published in Dedalo, while Federico Carbone of the University of Salerno showed the Coin Finds Hub of Italy, which is presented in Numishare. In either case, IT staff are often necessary to deploy these databases on web servers and/or handle the transformation and upload of data. There's no magic bullet in publishing excavation coins online without some level of technical support. We did discuss implementing a simple spreadsheet mapping tool into NUDS that could be uploaded in Numishare.

I expect both the Coin Finds Hub of Italy (which includes the excavations of Paestum, Pompeii, and others) and the Alexandrian coins to be available online later in the fall and integrated (at least to a small degree) to type portals such as IRIS, OCRE, or PCO.