Friday, December 20, 2019

1200 Hellenistic monograms posted to PELLA, and OCRE updates

As part of the larger NEH-funded Hellenistic Royal Coinages project, we have published over 1200 monograms (and open access SVGs) to PELLA through a new spreadsheet import mechanism in Numishare that is very much like the one we use for IDs in Nomisma. I have also updated the monograms for RIC 10 that had been published to OCRE already.

The data model follows recent agreements for crm:P106_is_composed_of for constituent letters and crm:P165i_is_incorporated_in for 1 or more digital images, as also recommended by the CIDOC CRM sig. Non-monograms are E37_Mark.

We haven't connected PELLA monograms to Price Alexander coin types yet, but that will be coming pretty soon. You can, however, take a look at what's possible in OCRE (, with a monogram displaying a map of related mints and a list of coin types.

The /symbols interface has a very simple system of selecting constituent letters, e.g.,

I plan to build something more sophisticated in that utilizes SPARQL of monograms aggregated from disparate datasets which will also allow more complex queries based on mint, authority, etc. based on connections between monograms and coin types (including geographic visualization).
This is the first step of facilitating some major research questions in Greek numismatics.

Merry Christmas!

Thursday, November 7, 2019

New Partners for Nomisma

Several new partners have joined the numismatic Linked Open Data ecosystem through the database network developed through the Berlin Münzkabinett. This software framework, which is used by about 20 collections in Germany and Austria, now supports the direct-to-Nomisma RDF export detailed in's documentation. Previously, I had written a PHP script to harvest LIDO XML files (one by one) that were listed in text files from each institution. At one HTTP request per second, it typically took about three hours to generate an RDF export for Berlin that I stored as a static file on the server. Now, it takes only a minute or two to ingest RDF VoID dataset metadata and data dumps directly from the Berlin database.

Now, about three-quarters of the 40 or so collections that contribute data to Nomisma offer direct RDF exports according to our specifications, which is a tremendous advancement toward sustainability of our ingestion workflow. KENOM offers an OAI-PMH API that I have scripted to harvest, and harvesting from the Bibliothèque nationale de France is a combination CSV processing/Gallica OAI-PMH harvesting. The remaining partners have been added into Nomisma by writing bespoke scripts for processing CSV into RDF and storing static files on the ANS server (often, this process includes having to use OpenRefine to map coin type references to URIs). I am hoping that in the next few years, we can transition completely to direct RDF ingestion via our VoID specification or Linked Art JSON-LD harvesting, which I have already begun to prototype in the Nomisma.or backend.

New partners include:
  • Augsburg University
  • Konstanz University
  • Mainz University
  • University of Vienna

These add more than 1,000 coins into, primarily for OCRE and CRRO.

Friday, September 27, 2019

First pass at processing Linked Art JSON-LD to Nomisma RDF

Over the last few weeks, I have been developing a harvester for Linked Art-complaint JSON-LD simultaneously in both and, which share similar frameworks that are built around Orbeon XForms for manually editing or transforming large quantities of data (usually CSV) to RDF, and connecting these workflows directly to Apache Solr and a SPARQL endpoint. These new features, in both platforms, load JSON-LD from a URL, which is transformed into the XForms 2.0 spec's JSON-to-XML model, and is then validated and parsed into RDF/XML on the way into the SPARQL endpoint.

I will write something more comprehensive about how this functions specifically on the Greek pottery side of things, but I have successfully tested transforming the Linked Art JSON-LD for a test coin ( into the hybrid data model that is composed of properties and classes from our own numismatic ontology and properties from other ontologies, like Dublin Core Terms and the Europeana Data Model.

This transformation process removes much of the developer-oriented cruft out of the JSON to distill the model specifically to the essential literals and URIs necessary for connecting a coin, its measurements, images, and coin type URIs to the numismatic knowledge graph in the SPARQL endpoint.

Basically, it performs the following functions:

  • Maps the preferred term for an object dcterms:title and the accession number to dcterms:identifier
  • Measurements (weight, axis, diameter) are mapped to the correct Nomisma property and validated to ensure that they conform to the correct units. Inches and centimeters will be converted to millimeters for diameter, height, width, and thickness.
  • Images for each "part" (obverse, reverse) are placed into the appropriate nmo:hasObverse or nmo:hasReverse data object as foaf:depiction. IIIF service URIs are expanded into the edm:WebResource and svcs:Service model that we have appropriated from the Europeana Data Model specification.
  • Any top-level "type" (classified_as) that is not a Getty or Nomisma URI is presumed to be a coin type. We would like to discuss this further with the Linked Art community to formalize a method by which we can flag coin type URIs in a more stable and consistent manner.

It should be noted that Linked Art hasn't delved deeply into provenance, which would be necessary for encoding coin hoard URIs and findspot metadata.

You can see the resulting RDF/XML (that would get sent into the Nomisma SPARQL endpoint) here:

This harvester will be adapted as changes are made to the Linked Art model. We hope that this feature in Nomisma will open the door to more streamlined and consistent aggregation of numismatic materials from the broader museum community, especially as we begin to work on new projects that are relevant to the American Art Collaborative.

Tuesday, September 3, 2019

KENOM Updates in Projects

The State Museum of Prehistory Halle (Landesmuseum für Vorgeschichte Halle) is the latest partner to join the Linked Open Data cloud through the KENOM portal of German civic museums. Over 300 coins have been added to OCRE and CRRO from the State Museum of Prehistory Halle. In total, KENOM has made more than 10,000 coins available into the Nomisma numismatic ecosystem, for every type corpus project published by the American Numismatic Society--including Art of Devastation, to which no one besides the American Numismatic Society has contributed. There are 19 coins from two KENOM-affiliated museums made accessible through Art of Devastation.

The Holzthaleben Hoard in the distribution of RIC Claudius Gothicus 18.

The script that harvests LIDO XML from KENOM's OAI-PMH web service has been updated to make use of findspot metadata. About 150 coins are linked to Geonames URIs as single finds and another 100 are linked to two hoard URIs published by KENOM. These will ultimately link to the Oxford Coin Hoards of the Roman Empire project. The hoards are Schwabhausen and Holzthaleben.

Wednesday, August 14, 2019

Recommendations for numismatic spreadsheet standardization

Over the years, we have considerably refined the way in which we organize our spreadsheets for processing into NUDS XML files and upload into the Numishare platform. Our workflow started with Online Coins of the Roman Empire, where numerous interns worked over the course of four years (the final three funded by the NEH) to produce dozens of spreadsheets (typically one per emperor) encompassing more than 40,000 types.

Many of the primary typological categories, such as denomination, mint, and authority, contained Nomisma URIs, and textual categories, e.g. legend and type description, were columns of free text. These spreadsheets (Excel files) were exported into CSV and processed through a PHP script that I wrote to transform each row into a NUDS document, and then this batch of files would be uploaded with the eXist-db XML database client into the appropriate Numishare collection. After this, I would manually edit the code in the Admin panel in Numishare to index the most relevant batch of RIC IDs into Solr for the public-facing browse and search interfaces (so as not to reindex an entire collection of 40,000 types when a new or updated spreadsheet might only contains several hundred items).

With the publication of PELLA in 2015, we implemented a key->pair stylesheet that enabled us to connect obverse and reverse type description codes to each unique description, with columns for English, French, and German translations. The OCRE PHP script was modified to accommodate this new model. Subsequent type corpora have been published for Ptolemaic and Seleucid coinage, each with a slight variation of yet another PHP script. Furthermore, with partners in the Netherlands, Switzerland, England, and Italy deploying their own Numishare collections for type corpora and/or collections of physical specimens, the wide range of slightly different spreadsheet models require an ever-diverse set of scripts that need to be manually maintained. It has long been a goal of mine to implement a standardized spreadsheet import into Numishare itself, modeled on the XForms-based validation and transformation of Google Sheet's Atom XML API implemented several years ago in

Mapping Google Sheets columns to NUDS elements

Finally, after about a month of development and testing, a Google Sheets-based spreadsheet import is functional in Numishare. It is primarily focused on type corpora at the moment, as not all of the physical and administrative descriptors have been implemented for mapping spreadsheet column headings of numismatic objects.

Some things remain the same:
  • Typological categories must map to Nomisma URIs
  • References for physical objects can be a coin type URI of some sort, a plain literal, or a combination of a type series and type number separated by a | character. The type series must be a literal or a Nomisma URI for a type series, but I am to enable support for Zenon bibliographic URIs
  • Parent IDs (skos:broader) and deprecation-related IDs (dcterms:replaces or dcterms:isReplacedBy) must be contained in the spreadsheet.
  • A question mark can trail a Nomisma URI to denote uncertainty. This is parsed in the XForms engine to insert the appropriate uncertainty URI into the NUDS XML. 
  • Columns for symbols/monograms located at certain positions on the obverse and reverse can be mapped to the positions listed in the Numishare config.

Structured XML produced from a spreadsheet

Other types of information requirements must be met in order for the spreadsheet to validate, which means that certain data must be explicit and not automatically inserted by a script. For example, each NUDS XML document requires a title. This title was typically generated in the PHP script by some concatenation of a human-readable string with the type number parsed from an ID column. Similarly, all coin types and all physical specimens NOT linked to a coin type URI must have an Object Type URI in the spreadsheet, even if that URI for all objects is nm:coin.

All of this normalization can occur in a pre-processing phase in OpenRefine: automatic generation of titles through regular expressions, reconciliation of typological columns to Nomisma URIs through Nomisma's OpenRefine API, etc.

This new spreadsheet import also requires type descriptions to be present in the typological spreadsheet, which means rethinking the way in which descriptions are connected to the main typology spreadsheet. Instead of a separate stylesheet spreadsheet of key->pair combinations between codes and translations, this stylesheet is incorporated as a second sheet in the typological spreadsheet. It is therefore possible to create a VLOOKUP formula between the unique type description code in the typology sheet and the corresponding column in the description stylesheet (see Therefore, the type descriptions can still be maintained with the ease of making one change to a description in Sheet #2, and the change will immediately propagate into the Atom feed.

VLOOKUP to control type descriptions

I have applied the same logic for concordances. A single concordance sheet can be maintained and propagated across multiple relevant  type corpora.

See for example the Svoronos 1904 corpus of Ptolemaic coinage:

This contains a partial concordance between Svoronos numbers and the types from Catharine Lorber's Coins of the Ptolemaic Empire vol I, part I (gold and silver from Ptolemy I - IV as published in Ptolemaic Coins Online).

By eliminating the intermediary scripting and XML upload/indexing process, scholars will be able to use OpenRefine to prepare their data without much technical intervention and publish their type or specimen data into Numishare without significant IT overhead. This alone will save me quite a lot of time: a month of development up front to save at least the same amount of time per year in redundant scripting and OpenRefine data cleaning.

After a spreadsheet is uploaded, it will be indexed directly into Solr, if the types are active (not deprecated by newer URIs) and the indexing option has been enabled.

Full documentation of the spreadsheet upload is forthcoming.

Monday, August 5, 2019

Museum of Fine Arts, Boston joins numismatic linked data cloud

The Museum of Fine Arts, Boston is the newest entrant into the Linked Open Data cloud, providing data for more than 1,600 Roman Republican and Imperial coins to Coinage of the Roman Republic Online and Online Coins of the Roman Empire. The MFA's collection is particularly strong with respect to late Roman gold pieces, many of which represent the sole specimen available for that typology in OCRE.

Solidus of Constantius II (MFA 65.270), RIC VIII Rome 291.
Of these coins, roughly 1,400 are Imperial and a little over 200 are from the Republican period. The MFA's terms of service are linked from the datasets page in itself and the contributors pages in OCRE and CRRO.

Data for these coins were provided by Laure Marest, Cornelius and Emily Vermeule Assistant Curator of Greek and Roman Art, and processed through OpenRefine to reconcile against the APIs available in both projects. The resulting CSV was transformed into RDF by a script I wrote and uploaded here and ingested into Nomisma's SPARQL endpoint.

Wednesday, July 24, 2019

More than 600 BnF Ptolemaic coins added to PCO

More than 660 Ptolemaic coins from the Bibliothèque nationale de France have been added into the numismatic Linked Open Data cloud and are accessible through Ptolemaic Coins Online and the broader Hellenistic Royal Coinages umbrella site. There are now about 2,400 Ptolemaic coins in PCO (which includes at this phase the gold and silver coinage of Ptolemy I - IV, ca. 330-200 B.C.), and roughly 75% of these are from the BnF and American Numismatic Society. Therefore, high resolution, public domain images are available for reuse for these objects through IIIF web services. In total, 572 of 984 total Ptolemaic types are linked to at least one photographed specimen--almost 60% of the corpus in total.

Tetradrachm of Ptolemy IV, CPE I.1, 925.

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.

Thursday, January 31, 2019

New grid display implemented in Numishare

I have made an update to the Numishare browse page (which affects Mantis, OCRE, and various other projects) to enable changing the layout from the default list view (a row for each coin or type with thumbnails on the right side of the row) to a grid layout that makes it easier to browse visually by making the images more prominent. This layout is similar to the "Examples of This Type" section on coin type pages or the Identify a Coin interface in OCRE.

The list view is still the default view for the browse page, but the layout can be toggled by clicking the relevant icons on the row that contains sorting functions (just below pagination).

Archaic electrum coinage from Sardis

Thursday, January 24, 2019

University of Kiel joins Nomisma

Through the NUMiD consortium of German university numismatic databases (built on the Berlin Münzkabinett technical framework), the University of Kiel is the newest member of Nomisma.or, contributing over 200 Roman Republican and Imperial coins to OCRE and CRRO.

Example of RIC Otho 8.

There are now 34 contributors to OCRE providing data for more than 122,000 coins.

Friday, January 18, 2019

Formalizing editors and a step toward minting DOIs for Nomisma

As I reported in early October 2018, we made a huge improvement in data provenance, connecting concepts to individuals who contributed to those concepts by means of manual editing or curation of spreadsheets uploaded into the system.

All of the editors within Nomisma have their own URIs, often connected to ORCID. We implemented two concept schemes to separate the id/ and the editor/ namespace. I have finally made some updates to the HTML serializations of the editor/ namespace page and each editor URI in order to provide greater context about a person's contributions to Nomisma.

Editor Concept Scheme page

The editor concept scheme page now contains a list of editors in These are the people who have contributed one way or another toward the creation of IDs, even if they are not among the few who have been granted authenticated access to the Nomisma back-end, for example, in the creation of IDs to support publication of type corpora (Gunnar Dumke, Oliver Hoover, Vladimir Stolba, and others). This table is generated by a simple SPARQL query that includes an optional skos:exactMatch that contains an ORCID. I hope to be able to extend the RDF for each editor to include their organization affiliation (seen in Kerameikos at, which I copied and pasted over from one framework to another yesterday).

Editor pages

The editor pages are constructed by first submitting a SPARQL query to get a total count of IDs directly edited or contributed through spreadsheets. If the number is greater than 0, then two SPARQL queries are subsequently submitted to the Nomisma endpoint. One is to get a list of spreadsheets the editor has contributed to and the second is an abbreviated list of IDs associated with the editor. For example, I have contributed to about 2,500 Nomisma IDs, many of which have been through spreadsheet uploads ( Lists in each category are downloadable, and you can even download the entire subset of Nomisma concepts associated with me in RDF/XML, Turtle, or JSON-LD (not that these subsets are particularly important or useful by themselves--you might as well download the entire Nomisma dataset from the links on the home page). However:

DataCite XML Metadata for DOIs

The chief aim here, which is why we have sought to connect these Nomisma editor URIs with ORCIDs, is to be able to mint DOIs for each person that redirect back to the editor URIs. data constitute an enormous body of collective intellectual effort, and it's increasingly important that scholarly digital works receive equal weight as traditional publications. Therefore, the creation of DOIs for Nomisma contributions would appear in the scholarly profile in ORCID. Just recently, the AIA issued updated guidelines for the considerations of tenure and promotion, with specific guidelines for the recognition of digital projects, and so our goal of formalizing this recognition within Nomisma keeps us on the cutting edge with respect modern modes of scholarly communication.

At present, we are serializing RDF + SPARQL results into DataCite-compliant XML metadata, with the hope that we will be able to piggyback onto a partner institution's DataCite membership (at $2000/year, it is not justifiable for the American Numismatic Society to bear this cost). If this fails, I will rewrite my XSLT for Crossref (which now supports datasets), as the ANS is already a Crossref member, and has minted DOIs for electronic theses and dissertations and some other recent ebooks.