Friday, October 2, 2015

On Open Data and Numismatic Typologies

edit (2 October 2015, 4PM): I want to make it clear that we have been collaborating with numerous members of the Coins and Medals departments for several years now on a few digital projects, including building a close relationship with the Portable Antiquities Scheme. Data usage concerns have been expressed by a small handful of individuals at the British Museum and are not, as far as I can tell, driven by the Trustees of the British Museum.

Can the British Museum make their data available with a Creative Commons license, but then restrict how the data are used?

The short answer is yes.

But the long answer in this case is a bit more complicated. The British Museum has authorized the reuse of their data and images under a CC 4.0 BY-NC-SA license, meaning that anyone has the right to use these data for non-commercial purposes as long as the BM is attributed and the creative works derived from these data and images and likewise freely and openly shared. ANS collaborative projects have always adhered to these requirements. For OCRE, CRRO, and PELLA, we have extracted data from the British Museum SPARQL endpoint and transformed these data into the Nomisma ontology. The full list of datasets are available at, and so one may download the entire BM RDF data dump at once or extract any associated data via the Nomisma SPARQL endpoint. Individual coins are also attributed to their collection throughout the various interfaces in our digital type corpus projects.

As the British Museum license currently stands, we (or anyone) have the right to use these images and data in this manner, without the need to ask the BM permission to do so.

Only if the BM changed their license to the more restrictive ND (No Derivatives) would they be able to exert absolute control over the reuse of their data. This means that the public can only download a dump of their CIDOC-CRM RDF in N-Quads. It would not even be permissible to transform these data into RDF/XML for XSLT processing. One could not match the places in their thesaurus to Pleiades URIs and transform the CIDOC CRM into the Open Annotation model used for the Pelagios project. One could generate CSV out of the data to load into Open Refine, Google Fusion Tables for visualization, or to analyze data with R. Of course, a CC ND license would obliterate any potential for reuse of British Museum data, and this is certainly why they have not sought to place this draconian license on their data.

What does this have to do with typologies?

All of the numismatic data in the British Museum SPARQL endpoint are open, and nearly every individual specimen contains at least one reference to a coin type number. By poking around the BM data, I was able to figure out that the reference URI containing 'GC30' as a short title refers to Price's The Coinage in the Name of Alexander the Great and Philip Arrhidaeus. I developed a simple SPARQL query that allowed me to extract a list of nearly 3,000 coins from the British Museum that contained Price references. One could extend this query to gather a list of unique Price references rather than objects, and therefore anyone would be able to generate a significant portion of the typologies from the Price catalog. Now, this catalog would not be complete because Price derived some of his typologies from other collections, such as the American Numismatic Society. The BM endpoint also does not contain a full account of all Alexander coins in the BM collection.

However, these typologies from Price can be derived from descriptions of individual specimens, and the BM CC 4.0 BY-NC-SA license still applies. This begs the question: can the British Museum exert copyright control over typologies published in print when these same typologies can be freely and openly derived from its own collection database?

In fact, it would be possible to derive other typologies not under British Museum copyright by the same mechanisms. The same goes for the ANS database, which is freely and openly available with an Open Database License. Can the British Museum and ANS even include type numbers within their public databases if it is possible to derive typological data that might be under copyright of another publisher? In the United States, data aren't even copyrightable. And the use of reference numbers in databases, specifically, falls within the realm of Fair Use. If we begin to debate whether or not type numbers may even be referenced on the Web, the only real loser in this debate is the general public.

Proof of Concept: Seleucid Coinage, an American Numismatic Society publication

The URI for Houghton and Lorber's Seleucid Coins: A Comprehensive Catalogue Part I Volume I is

Poking around at the CIDOC CRM structure of the coins associated with SC references, I constructed a SPARQL query that would extract most of the typological data from the endpoint. It is a bit messy, as the SPARQL XML response tends to be with the expression of triples, so I took this XML response and wrote some basic XSLT to convert the response into CSV that better reflects individual typologies.

There are only 11 Seleucid coins in the BM system with Houghton and Lorber 2002 references, but I was able to generate a CSV file for all of the typological data for the SC types. The metadata are strings, but one could easily drop this CSV into Google Spreadsheets to clean up. If we were dealing with a typological dataset that consistent of thousands of types, it could be cleaned up in Open Refine in, probably, less than an hour to fully link all concepts to Nomisma URIs.

I have written a number of PHP scripts (e.g., like this one) to transform CSV into NUDS, and so one of these scripts could be adapted to transform the Nomisma-linked CSV into NUDS for direct publication in Numishare. It is possible to go from BM SPARQL queries to a fully-functional digital type corpus like OCRE in about a day's worth of work.

So basically, what I have done here is use the BM SPARQL endpoint to extract open data that comprise typologies that have been published by the ANS and are under ANS copyright. I mean, who cares, right?

Thursday, October 1, 2015

On Concordances Between Type Corpora

By now some of you may have heard that the British Museum issued a take-down notice for the PELLA project, a digital type corpus of Argead coins. PELLA will ultimately generate URIs for all Argead types, and will hopefully be the canonical corpus for cataloging both museum, archaeological, and private collections. The first and most important step in building a large scale digital corpus/data aggregation system (like PELLA, OCRE, CRRO, etc.) is to build a concordance between existing type numbers and future ones. This is especially the case for PELLA, as OCRE and CRRO are merely reflections of the current editions of Roman Imperial Coinage and Roman Republican Coinage. Therefore, Martin Price's 1991 out of print, but in copyright The Coinage in the Name of Alexander the Great and Philip Arrhidaeus is just one part of the existing print corpora of Argead coinage.

The British Museum "cannot consent to the Price catalogue typology being released online until we have been able to assess whether the Trustees of the British Museum would approve the inclusion of the Price catalogue material within this online resource" because they erroneously believe that the data published through PELLA are verbatim descriptions from the corpus. We can demonstrate significant enhancements of the typology, so this brings to question whether URIs for Price types can even be minted.

The BM seemingly does not want us to issue typological data under the Price numbering system, despite the enhancements that clearly deviate from the original publication. The BM would find it impossible to enforce this demand, as Price numbers are a standard reference for the coins of Alexander the Great, and nearly every collection uses these numbers--whether commercial auction houses, large museum collections like the ANS, Berlin, or Bibliotheque nationale de France, or tiny little museums like the University of Virginia Art Museum, which owns two Price-numbered coins of Alexander. The entire purpose of numbered type corpora like RIC, RRC, Price, etc. is to create a an up-to-date system by which scholars may cite coin types in a standardized way. Price's own corpus wasn't created in a vacuum. His typologies were influenced by those of his predecessors, going back for centuries.

This brings us to the important point of concordances. While PELLA will eventually issue a new set of unique identifiers for Argead coin types (based on a numbering system combining the ruler and mint), currently, the four collections that contribute data on physical specimens to the PELLA project use Price numbers in their databases. It is impossible to aggregate these collections without first establishing a baseline numbering system. It takes little effort to map these collections to Price URIs in PELLA. Moving into the future, there will be a systematic and transparent mapping from Price to future-URIs following Linked Open Data methodologies.

The fact of the matter is will NEVER, EVER go away.

Even after we have established a new numbering system, the price.4 URI will be a semantic HTTP 303 See Other redirect to the new URI if you go to price.4 in your browser. If you request RDF for price.4 via content negotiation, it will say that this type has been dcterms:isReplacedBy ale3.amphipolis.4 (or whatever). The RDF for ale3.amphipolis.4 will say that this is a skos:exactMatch for its preceding Price number.

The Berlin Münzkabinett has already begun to incorporate Price URIs from Pella into its database. But moving forward, because of the inherent functionality in Numishare for building sustainable concordances between coin types, Berlin will be able to update their database to the most current version of PELLA type URIs through automated mechanisms. The same would be true for the British Museum, if they want in due course to benefit from the work of others freely offered, for the incorporation of PELLA (or OCRE or CRRO...or Getty or Pleiades or Wikidata, for that matter) URIs into the "5 Star" Linked "Open" Data system. This is a topic for another time, but I am feeling increasingly inclined to discuss it.

According to the British Museum, "as far as we can see this catalogue data has not been updated to incorporate any new attributions and contains no new scholarly research." This, of course, ignores the tremendous scholarly effort in mapping typologies into the graph of data in the Nomisma ontology and concept namespaces, as well as the reorganization of obverse and reverse symbols in a way that makes query possible on the Web.

This brings me to my final point:

We are also concerned that the Open Database License (ODbL v1.0) under which the PELLA project is distributed is not compatible with the Creative Commons License (CC-BY-NC-SA 4.0) license that governs all non-commercial uses of images and data available both through the British Museum Collection Online and the British Museum Semantic Web Collection Online, as well as all non-commercial uses of any documents produced by the British Museum in any format or through any medium.

The PELLA data were created by Andy Meadows and Peter van Alfen, with translations into German and French provided by Karsten Dahmen and Frédérique Duyrat, and the ANS has every right to place an Open Database License on these data, since these typologies are enhancements over what was originally provided in Price. And of course, our migration of their data from CIDOC-CRM into the Nomisma Ontology and integration of it into the Nomisma SPARQL endpoint does not violate any terms of their CC license whatsoever. PELLA is a non-commercial project. We are sharing the data alike, and we are attributing the data to the British Museum, when applicable. And we have linked to the images that they are providing through their own system, which is perfectly acceptable for their CC license. No one complained when the British Museum became partners in OCRE or CRRO, so one has to wonder why they are causing such a stink with this particular project. The British Museum is stifling scholarship and undermining the potential for numismatic research and the integration of numismatic materials into the wider cultural heritage domain. We at the ANS support Open Data and Open Access, and we hope that future scholars may make use of these data for answering more complex research questions.

Friday, September 18, 2015

The American Numismatic Society Introduces Digital Library

The American Numismatic Society (ANS) continues its mission of providing Open Access research tools to researchers worldwide with its newly unveiled Digital Library ( The ANS Digital Library will grow to house three collections of digital material: numismatic theses/dissertations, auction catalogues, and ebooks.

Beginning now, the collection of electronic theses and dissertations hosts international doctoral work on numismatic themes. Anyone may browse the collection online, and are welcome to download any PDF or DOC file containing the research that earned their authors their MAs and/or PhDs. The ANS has seeded this space with the work of its own staff, and welcome any/all theses from numismatists, archaeologists, historians, and other scholars worldwide.

Andrew Reinhard, Director of Publications for the ANS, discussed the reasoning behind creating the collection. “Many numismatic doctoral theses and dissertations are never published, or they appear only in print that is accessible to very few people. The ANS is already an international destination for Open Access numismatic data, so it seemed logical that we also could be a hub for hosting advanced, groundbreaking numismatic scholarship.”

If you would like to have the ANS host and distribute your thesis or dissertation at no charge under a Creative Commons license, email the file(s) or link(s) to Once your work is uploaded, the ANS will publish its link, and will also create an entry in the DONUM library catalogue to aid discoverability.

Over the next few months, the ANS will begin to share freely its scanned auction catalogues as well as ebook versions of its monographs and series on this Digital Library platform.

For more information, contact Andrew Reinhard, Director of Publications, at 212-571-4470 ext. 111 or

Tuesday, August 18, 2015

Portable Antiquities Scheme in CRRO

The first archaeological materials have been linked into Coinage of the Roman Republic Online (CRRO). Yesterday, Dan Pett began working on linking Republican coins in the Portable Antiquities Scheme to URIs for Michael Crawford's RRC numbers in CRRO. Beginning with just four linked objects yesterday afternoon, in order to iron out the VoID and Nomisma data dump models, the number of PAS coins in CRRO has grown to 66 this morning. In total, we expect more than 1,000 PAS coins in CRRO by the time the database has been fully linked up.

The PAS coins have weights, axes, and diameters that can be used for quantitative analysis. Many have public findspots to show the geographic distribution of types, and of course, most have been photographed. RRC 322/1a, for example, contains links to two PAS coins, one of which has a findspot of Blyth, defined with a URI from the Ordnance Survey gazetteer.

Since most of the PAS Republican coins were minted in Rome, these new data have altered the heatmap distribution for the Nomisma concept of the mint of Rome, with a number of new findspots appearing in England, adding to the two findspots already recorded from Crisis of the Third Century hoards in which a number of University of Virginia Art Museum coins were found.

When the Republican coins in PAS are fully linked into CRRO, we expect that this will enhance the project's value as a research tool for investigating the circulation of Roman coinage into the British Isles.

Incidentally, I updated the underlying SPARQL query for the CRRO Contributors page to display coin counts and publisher information for coins which are not contained in museum collections (since the PAS database contains objects which may have been dispersed to a wide variety of public or private collections). These code updates affect Numishare in general, including OCRE.

Thursday, July 2, 2015

Migrated from OpenLayers to Leaflet in Nomisma, Implemented Heatmaps

I have spent a few days finding solutions to scalability problems loading a lot of points in OpenLayers, and migrated to Leaflet and implemented heatmaps, which reveal context in a more useful way when there are a lot of points. I wrote the following email to the Nomisma list:


We had run into scalability issues with rendering maps of findspots driven by SPARQL for mints in the Nomisma interface. It was not a triplestore issue, but a browser issue. OpenLayers did not handle 1000 points for findspots related to Rome gracefully, so I had to change directions.

First, it should be noted that the the points now reflect unique findspots and not objects (because we can't reasonably map 10,000 coins found in the same hoard, therefore the same findspot).

I switched OpenLayers to Leaflet. I replaced the default KML rendering of points into a heatmap, which is more indicative of distribution overall. See for example, but you can also see for the distribution of (mostly Republican) coins using Sicily as the nmo:hasMint. The IGCH findspots are in the system, so a number of Greek mints have hits as well (

There are four available base layers. The default is the ancient terrain produced by the Ancient World Mapping Center at the University of North Carolina and hosted by Also available are modern terrain, OpenStreetMap, and the Roman Empire map.

You can toggle the main point/polygon for the mint/region on or off, as well as the heatmap. You can also turn on the KML layer (which is still available for individual download as well). Leaflet seems to handle a large number of points more efficiently than OpenLayers.

This migration to Leaflet is the beginning of really sophisticated geographic analysis tools that I would like to implement into Nomisma. There are a lot of ways we can make Nomisma data more useful to researchers.

Tuesday, June 23, 2015

Antike Fundmünzen in Europa (AFE) in OCRE

More than 800 coins from Antike Fundmünzen in Europa (AFE), a Römisch-Germanische Kommission (RGK) (a Nomisma partner), have been ingested into the Nomisma triplestore. Of these, only a few dozen are directly linked to URIs in OCRE, but the remaining coins are still available for query by means of directly affiliated triples (such as this SPARQL query below, which gathers a UNION of coins with Vespasian explicitly designated as authority and those that are implied by means of a linked coin type).

SELECT ?object ?type ?weight ?diameter WHERE {
  { ?object nmo:hasAuthority nm:vespasian ; a nmo:NumismaticObject }
  UNION { ?type nmo:hasAuthority nm:vespasian ; a nmo:TypeSeriesItem .
         ?object nmo:hasTypeSeriesItem ?type }
  OPTIONAL {?object nmo:hasWeight ?weight}
  OPTIONAL {?object nmo:hasDiameter ?diameter}

These are the first archaeological materials ingested in Nomisma, each with findspots.

See, for example, of a Vespasianic coin type with a findspot and measurements from the AFE database.

Thursday, June 18, 2015

Berlin coins updated in OCRE and CRRO

The Berlin LIDO/XML export data for Roman Imperial Coinage references has been reprocessed, and coins from the Münzkabinett from Valerian through Quintillus are now available in OCRE. The number of imperial coins from Berlin grew about 150 to 3,749. Additionally, the RRC export was reprocessed into RDF following the new Nomisma ontology, and the total number of Republican coins from Berlin available in CRRO has grown to 1,080. The ANS coins for RIC V were updated yesterday, and the University of Virginia coins just before that. I expect to update the RIC V coins from the British Museum in the near future. This will add over 2,000 more coins to OCRE.

Presently, nearly 35,000 coins from the ANS, British Museum, Berlin, and the University of Virginia are available in OCRE. I expect the first batch of archaeological materials from Antike Fundmünzen in Europa (AFE) to be ingested into the Nomisma triplestore soon. This is a tremendous milestone.