Friday, June 7, 2019

Upgrades to research context in Nomisma's user interface

After several days of development, I have pushed some significant changes to the user interfaces regarding additional context for certain types of entities defined in the system. Building on recent advancements that I made in increasing the complexity of typological and metrical visualizations in both Nomisma and the Numishare platform (specifically for Hellenistic Royal Coinages), I have introduced the same sorts of queries for the geographic APIs (that serialize SPARQL queries for mints, findspots, and hoards associated with a Nomisma concept into GeoJSON for display in Leaflet) and the list of related coin types.

Using the relationships inherent in Nomisma's data, we are now able to visualize the geographic distribution of corporate authorities, dynasties, and people appearing on portraits. For example, in order to generate a map illustrating the distribution of mints for the entire Seleucid Empire, the SPARQL query will search for coin types with an nmo:hasAuthority of a person who has an org:hasMembership/org:organization of

In introducing this new level of complexity, I rewrote a significant portion of the pipelines underlying these URIs to migrate from a large series of hand-coded SPARQL templates in which small portions were replaced with simple string replacements to a more generalizable and flexible system built around using XSLT to generate a complex XML metamodel for a SPARQL query, which is then serialized by another set of XSLT templates into the SPARQL text that is POSTed to the endpoint.

New interface for, showing related coin types and a map of all Seleucid mints and known IGCH hoards and one single find.

As a result, the following improvements in mapping and/or related coin types have been applied to the following categories of SKOS concept:

Additionally, some updates were made to the distribution and metrical analysis SPARQL templates to query based on portraiture from the ID page ( This had previously not been possible--one had to use the purpose-built visualization interfaces and select "Portrait" as a facet.

The distribution of deities between Faustina and Antoninus Pius, as generated on the ID page for Faustina.

Having migrated to this new metamodel system for the generation of GeoJSON for geographic queries, it will be possible to enhance the complexity to iterate beyond queries about one particular Nomisma concept to queries that involve more than one parameter (such as those in the distribution and metrical visualization interfaces). That is to say, it will be possible eventually to not only generate a map showing the mints that produced tetradrachms, and where tetradrachms have been found in hoards, but where the tetradrachms of Ptolemy I have been produced and found. While Numishare contains a map interface that enables the display of mints pertaining to a query (driven by Apache Solr, the search index for Numishare), the indexing of findspots into Solr was disabled a year or two ago due to problems with scaling and the wait time for indexing a type corpus as large as OCRE. The next step is to rewrite the Numishare map interface to interact with Nomisma's SPARQL endpoint directly to display mints and findspots (which always reflects the current data ingested into the Nomisma linked data cloud), rather than rely on Solr.

Another major update is looming on the horizon, probably to come within the next few weeks: enhanced data for Roman Imperial persons. Presently, Hellenistic kings have been thoroughly integrated with Nomisma URIs for dynasties and corporate entities, but these are lacking in the Roman world. The Roman committee is currently working on a revised spreadsheet of people in order to add new dynasties and corporate bodies into the system, as well as start and end dates for the reigns of Roman emperors. This means that we can compare visual motifs between the Julio-Claudians and the Flavians or compare the change in weights of antoniniani between the Gallic Empire and the Roman Empire (Valerian to Gallienus) over the same time period.

Additionally, dynasties and corporate bodies will be introduced as facets in OCRE. We are also working on a spreadsheet of Roman provinces, which will also be introduced as facets in addition to historical regions. The Region facet in OCRE is currently a conflation of provinces and historical regions owing to inconsistencies in RIC's structure.

Monday, June 3, 2019

ANS releases Hellenistic Royal Coinages

The American Numismatic Society (ANS) is pleased to announce the launch of a new online resource, Hellenistic Royal Coinages (HRC)( A National Endowment for the Humanities funded project based at the ANS in New York City, HRC is a web-based resource for users to learn about, research, and conduct different types of statistical analyses on the coinages produced by the different dynasties and rulers of the ancient Mediterranean and Near East during the Hellenistic period (ca. 323–31 BC). These include the coins struck by (and in the name of) Alexander the Great and those struck by his successors, such as the Seleucids in the Near East and the Ptolemies in Egypt.

The new HRC website serves as a Union Catalogue of existing online resources devoted to Hellenistic coinages and allows users to search across all these sites simultaneously. These sites include: PELLA (, a resource that currently focuses on the coinage in the name of Alexander the Great; Seleucid Coins Online (, a resource devoted to the coinage of the Seleucid dynasty; and Ptolemaic Coins Online (, a resource for the coinage of the Ptolemaic dynasty. In the future we hope to add additional resources for the coinages of other Hellenistic dynasties and rulers including the Antigonid, Attalid, and Bactrian dynasties.

Currently over 31,200 individual coins from seventeen institutions are illustrated and described in the HRC catalogues. While the American Numismatic Society’s collection serves as the core of all these searchable catalogues, thousands of examples are illustrated by links to coins in other major collections including those in the Bibliothèque nationale de France, the British Museum, the Münzkabinett der Staatlichen Museen zu Berlin, and other public collections in the US and Europe.

ANS Executive Director Ute Wartenberg notes that “the HRC website promises to transform the way in which scholars, collectors, and others research and learn about Hellenistic Coinages.”  

The American Numismatic Society, organized in 1858 and incorporated in 1865 in New York State, operates as a research museum under Section 501(c)(3) of the Internal Revenue Code and is recognized as a publicly supported organization under section 170(b)(1)(A)(vi) as confirmed on November 1, 1970.

Wednesday, May 15, 2019

Extending distribution and metrical analyses across corporate entities

I recently pushed some significant changes to the distribution and metrical analysis visualization features both in the Numishare platform and itself to differentiate personal from corporate authories when querying typological data.

Previously, the authority could be selected as a query parameter for generating a visualization, but the underlying SPARQL query merely extracted the values associated explicitly with the nmo:hasAuthority property for coin types. This means it was impossible to compare one kingdom to another since the relationship between a type and an overarching corporate entity is nearly always made between the ruler designated as the nmo:hasAuthority and the ruler's Nomisma RDF that links the ruler concept to the corporate entity using the W3C organization ontology. For example, Ptolemy I is linked to the Ptolemaic Empire with the following model:

nm:ptolemy_i org:hasMembership ?membership .
?membership a org:Membership ;
    org:organization nm:seleucid_empire;
    org:role nm:authority.

Using this model, we are able to use the Nomisma SPARQL endpoint to extract the distinct corporate entities that minted tetradrachms with the following query:

SELECT DISTINCT ?kingdom ?label WHERE {
  ?coinType a nmo:TypeSeriesItem;
              nmo:hasDenomination nm:tetradrachm .
  {?coinType nmo:hasAuthority ?kingdom}
  UNION {?coinType nmo:hasAuthority ?auth .
        ?auth org:hasMembership/org:organization ?kingdom }
  ?kingdom a foaf:Organization ;
             skos:prefLabel ?label FILTER (langMatches(lang(?label), "en"))

Bear in mind that we have to use a UNION query to join coin types that may have the corporate authority explicitly expressed in the nmo:hasAuthority. This is the case for later Seleucid coinage issued under the authority of the Roman Republic.

Now that we are able to exploit the relationships between people and corporate entities in the Nomisma data, we can begin to construct new queries and visualizations across broader periods of time, for example to compare the average weights of tetradrachms issued broadly by the Seleucid vs. Ptolemaic Empires over nearly three centuries. Or to compare the distribution of deities that appear on Seleucid vs. Ptolemaic coinage (for example,

Distribution of deities as appearing on Seleucid and Ptolemaic coinage

Here we can see the Ptolemaic affinity toward Athena compared to the prevalence of Apollo on Seleucid coinage, at least according to the the incomplete typological data we have published from the Ptolemaic Empire (Ptolemaic Coins Online only coins the gold and silver coinage through Ptolemy IV so far). This is one of a number of recent improvements to the query mechanisms in Numishare and Nomisma, and more should be expected in the coming months, especially to include the querying of legends and monograms.

Tuesday, April 9, 2019

4,450 Seleucid coins from the Bibliothèque nationale de France added to SCO

This morning I received a new spreadsheet from Julien Olivier of the Bibliothèque nationale de France with approximately 6,500 coins connected to URIs defined in PELLA and Seleucid Coins Online. Some 2,000 Alexanders from the BnF have been incorporated in PELLA for quite some time, but we are happy to announce this latest export includes 4,450 coins from the Seleucid Empire. This nearly doubles the number of specimens available in SCO. The ANS has contributed about 4,800 itself. There are now nearly 9,700 physical coins linked to about 2,500 parent types in SCO.

Furthermore, all of the coins from the BnF are photographed and high resolution imagery is available through the IIIF protocol.

SC 379 (Antiochus I tetradrachm) is one of the best represented specimens.

Tuesday, April 2, 2019

D3js-based Charts Migrated to Production

Although I am still working on ironing out some issues with full internationalization of the interface and SVG/image downloads of charts, the new interface has been pushed into the production installation of Numishare, so these new features are now available in OCRE, CRRO, and the Hellenistic Royal Coinages projects. I have yet to create a forwarding mechanism that will parse request parameters for the first iteration of the metrical analysis interface and generate a new series of parameters for the current one. I should have that functioning by the end of the week.

Comparing weights of denarii and antoniniani over three centuries.

The chart above (linkable here) illustrates the change in average weight of denarii and the introduction and evolution of the antoninianus from 30 B.C. to A.D. 300. The antoninianus, introduced by Caracalla in 215, was intended to be valued as twice that of the silver denarius, but as we can see from the wealth of measurement data we have (42,702 weighed specimens connected to RIC types within this date range [see for the SPARQL query]), the average weight of antoniniani minted in 215-220 is 4.88g, which is only 59% heavier than the denarii minted during the same period.

So already, the Roman Empire is cutting corners economically by issuing "double" valued currency with lower levels of weight/silver content. Citizens would have been better off hoarding denarii.

In the next five-year span, the weight of antoniniani goes up a bit while the denarii go down, resulting in a roughly 1.7:1 ratio, but denarii are still prominent in production, comprising 42% of all denominations minted during this period, compared to about 3% for antoniniani (

After 240, by the time we reach the beginning of the Crisis of the Third Century, the average weight of the antoninianus declines precipitously until it hits rock bottom from about 265 to 275, when it barely weighs above (or even below, briefly) the denarius. At this point, production of silver coinage in the Roman Empire transitions almost exclusively to the antoninianus, 64% to 6% for denarius and quinarius (the remaining 30% being bronze or gold [see data here]).

Distribution of denominations produced 260-274.

The denominations begin to increase in weight and value beginning in 275 as the Roman Empire begins to emerge from its three decades of internal strife and hyperinflation, though the antoninianus will never come close to recovering its intended 2x value.

These, of course, are facts we already knew through intensive study of the Roman economy. But we have a wide variety of typological and metrical data available, enabling us to generate visualizations and downloadable CSV (that can be integrated into other statistical/data science platforms) much faster than ever before. If our data tell us what we already know, then we can be confident that new research questions developed upon these data will yield accurate results.

Thursday, March 28, 2019

Migrating quantitative analyses in Numishare to d3.js

I have spent the last few weeks making some significant updates to Numishare in order to accommodate two scenarios in publishing coin type corpora online within the framework:

  • To create an umbrella site that encompasses PELLA, Seleucid Coins Online and Ptolemaic Coins Online for the NEH-funded Hellenistic Royal Coinages project. This requires some updating of the Numishare config to include URIs for multiple type corpora to join SPARQL and Solr queries together for the browse interface, geographic visualizations, and quantitative analyses.
  • To make it possible for a digital type corpus to completely stand alone with its own SPARQL endpoint (for Clare Rowan's project on Roman tokens). Although a SPARQL endpoint can be specified in the Numishare config, various parts of the application still relied on APIs for displaying related specimens in the browse page or average weights and diameters on coin type record pages. This makes it difficult to test the development of a type corpus since types are not ingested into until they are completed, and specimens are not integrated into Nomisma until they have been assigned permanent URIs.

As a result, I have successfully implemented the joining of SPARQL and Solr queries for the HRC umbrella site, which I hope we can launch by May (even though Ptolemaic Coins Online is only partially completed).

Map of the full distribution of Seleucid and Ptolemaic coinage, based on current data.

It is now possible to compare the average weight of tetradrachms of Ptolemy I with those of Antiochus I through one interface that enables the query across these disparate datasets.

Since I had to conduct significant revisions to the underlying SPARQL queries in Nomisma to facilitate these joins, I moved forward with a task that has been on my agenda for the last three years: to migrate the semi-proprietary Highcharts Javascript library to the much more robust and community-supported d3.js. I had previously implemented this library for distribution and metrical analyses in itself. So I adapted code I had already written in Nomisma in order to generate APIs in Numishare that would construct complex SPARQL queries from URL parameters and serializing the resulting output into the JSON model required by d3.js. Like Nomisma, the API will also serialize the results into CSV for further revision or analysis in other platforms.

The average weight tetradrachms of Ptolemy I and Antiochus I

Unlike the Nomisma interfaces, which are exclusively in English, I have adapted those in Numishare to provide the results in each of the languages supported by the framework. If a preferred label exists in Nomisma for a given concept, it will be displayed. If not, it will default to English.

Distribution of denominations produced by Antiochus I vs. Ptolemy I, in French

Before these updates, the metrical analyses in Numishare were built on SPARQL, but the distribution visualizations were based on facets indexed into the Solr search index. These Solr facet-based distributions applied to both coin type and physical specimen collections. The old /visualize link will continue to exist in Numishare, particularly for specimen collections, but a warning message informs user of type corpora that the Solr-based distributions will be deprecated eventually. The Solr distributions are particularly powerful because the Solr queries might include searches for legends, iconographic descriptions, and fuzzy searches with wildcards. This can be implemented in SPARQL eventually, but the new interface currently only allows queries for typological categories connected to Nomisma-defined concepts (denominations, people, mints, etc.), as well as start and end dates.

The Solr-based distribution analysis interface has also been migrated from Highcharts to d3.js, and an API has been adapted to transform a series of Solr queries (for comparisons) into the d3.js JSON model (with optional CSV downloads, also).

Distribution of mints of Antiochus I to Seleucus I

I have compared the result of these charts derived from Solr with those derived from SPARQL, and the resulting statistics are identical. They weren't in the initial testing, as the first version of the SPARQL query including all subtypes as well. But any type that has a skos:broader property has been suppressed from the query, enabling a consistent comparison of parent types. The charts derived from Solr are multilingual only if the language has been enabled in the Numishare config and the types have been reindexed into Solr following the activation of these languages in the interface.

Since metrical analyses are being fully migrated to d3.js with a different array of HTTP request parameters, old URLs that point to these charts will be forwarded to the new URL pattern to maintain backwards compatibility.

This migration from Highcharts to d3.js is nearly complete, and I hope to move this significant changes to production by the end of April. Expect the Hellenistic Royal Coinages umbrella site to be launched sometime between late April and mid-May.

Highcharts remains for data visualization in Coin Hoards of the Roman Republic, but this will be migrated next.

Wednesday, March 6, 2019

University of Mannheim joins Nomisma

The University of Mannheim digital coin cabinet, part of the NUMiD consortium, has made 29 Roman imperial coins available in OCRE.

Examples of RIC Hadrian 396
Mannheim is the 35th contributor to OCRE. Roughly have of all institutions contributing to OCRE are from NUMiD.