Friday, May 19, 2017

Nomisma measurement analysis interface ready for wider testing

I have been working on and off for the last month or two on a new quantitative analysis feature in Nomisma, which is available on pages for certain types of Concepts (that are associated with coin types that have been ingested into Nomisma) as well as on a new page,

Much like the distribution analysis interface, the user can select multiple dataset groupings to compare for average weight or average diameter. Optionally, and like the existing features in OCRE, CRRO, and PELLA, the user can input a start date and end date and an interval of 5 or 10 years in order to visualize the change in average weights over time. The parameters established in the web form are used to query a web service, which interacts with Nomisma's SPARQL endpoint and serializes the response into JSON for visualization.

Average weight of denarius (red), aureus (yellow), and antoninianus (blue) from 100 BC to AD 300. See for yourself.

What separates this interface from the feature that is built into Numishare projects (like OCRE) is that the weights are drawn from all relevant coins, regardless of an explicit connection to a coin type defined by a URI published by OCRE or similar project. This means that coins from Antike Fundmuenzen Europa or other finds databases that do not have positively identifiable RIC numbers can be queried alongside those that do, as long as those relatively uncertain coins still have some certain attributes, such as authority or denomination. Moreover, these interfaces allow the querying across related, but separate datasets--e.g., to evaluate the change in average weight of denarii from 100 B.C. to A.D. 100, even though the denarius coin types are split between OCRE and CRRO starting about 27 B.C.

The raw data can be downloaded as CSV for further analysis, visualization, or publication, and the chart for the metrical analysis page can be reproduced easily by bookmarking the resulting URL.

Weight of Augustan denarii from Rome compared to Lugdunum

Known Limitations

The metrical analysis feature is still a working proof of concept that will be refined and enhanced over time.

First, we do encounter coins that are either cataloged with the wrong RIC number or the automated matching script erroneously interprets a reference into the wrong RIC number, so the weights of these coins may have an effect on the overall average for a query. I think, in most cases, the margin of error is quite small.

The charts are visualized with a d3.js plugin called d3plus. There's an error in the handling of BC dates (according to the ISO spec), and so (in interval queries), the dates are converted to an integer value. So -100 is 100 B.C. and 200 is A.D. 200. As a result, the d3plus line graph cannot be set as a timeline, and therefore date ranges that do not contain weight data are removed from the chart. It is important to be able to visualize gaps in weights, as these gaps may illustrate periods where coin types conforming to a query were not issued (for example, there is no weight data for aurei from 70-50 B.C.).

One last thing to note is that I have not been able to manually override the x-axis labels, so -100 actually means 100 B.C. to 96 B.C. when the interval is set to five years (not just 100 B.C.). The human readable date range is still available when hovering the mouse over a point in the chart and in the CSV download.

Next Items

Aside from minor alterations that should come when d3plus's B.C. date glitch is fixed, I plan to expand beyond average weight and diameter to showing weight+diameter as a cluster as well as standard deviation for measurements, which should be more illustrative of coins that do not conform with the norm, enabling them to be eliminated from further weight query, while also flagging them to collections as potentially erroneously attributed coins, counterfeits, partial specimens, or other such aberrations.

Friday, May 12, 2017

Extending Nomisma geoJSON for Temporal Data

The geoJSON output for queries for findspots and hoards associated with concepts has been updated with the geoJSON-T extension, including closing or burial dates of hoards or individual finds, when known. Additionally, the properties following the geoJSON-T proposed model for gazetteer toponyms and URIs, e.g.:

      "type": "Feature",
      "label": "Meolo (Albaredo d'Adige) (Italy; ME2)",
      "id": "",
      "geometry": {
        "type": "Point",
        "coordinates": [
      "when": {
        "timespans": [
            "start": "-0038",
            "end": "-0038"
      "properties": {
        "toponym": "Albaredo d'Adige (Italy)",
        "gazetteer_label": "Albaredo d'Adige (Italy)",
        "gazetteer_uri": "",
        "type": "hoard"

Furthermore, the getFindspots, getHoards, and heatmap APIs have been updated to accept a coinType request parameter instead of an id parameter in order to get relevant geographic data associated with coin type URIs, rather than associations with Nomisma-defined numismatic concepts. This is the first step in the eventual overhaul of the mapping features in Numishare coin type projects (like OCRE) to render geoJSON-T in Leaflet, finally retiring the TimeMap plugin that has not seen active development in at least four years.

Tuesday, May 2, 2017

KENOM project joins Nomisma/OCRE

The KENOM project, a consortium of 13 German institutions contributing into a central numismatic portal, has been integrated into More than 4,500 Roman Imperial coins from three institutions (The State Coin Collection of Munich, the Coin Cabinet of the University of Goettingen, and Thuringian Museum for Pre- and Early History) have been made available Online Coins of the Roman Empire. All of these coins have been photographed at a high resolution and are published following the IIIF specification, which are treated as zoomable images in OCRE, and will eventually be useful for more sophisticated iconographic annotation.

Augustus 171A

Below is a fuller description of KENOM:

KENOM (Kooperative Erschließung und Nutzung der Objektdaten von Münzsammlungen) is a long time project of different numismatic collections in Germany to bring their numismatic objects (coins, medals, paper money and also coin find-informations) together online. There are a common internal database of the project for the data input and a portal of presentation of qualified data and images. Goals of KENOM are the harmonisation of numismatic data of the partners, the integration of open linked norm data and the definition and use of a LIDO-based data exchange format. 2012-2015 the project was funded by the Deutsche Forschungsgemeinschaft, now KENOM is operated jointly. The strong technical partner of the project is the Gemeinsamer Bibliotheksverbund Göttingen. Today already 13 institutions present more than 33,000 numismatic objects together in the portal <>.

KENOM has developed lookup mechanisms that read OCRE and CRRO web services, making it easy for curators to link their collections directly to these Linked Open Data systems. The RDF data for OCRE were harvested from KENOM's OAI-PMH using a PHP script I put together yesterday afternoon. Project coordinator, Mario Schlapke, plans to write a more comprehensive post about the process of integrating KENOM with the wider ancient world linked data cloud.

Thursday, April 27, 2017

OCRE launches new interface to aid in identification of Roman coins

After years of discussion and labor by several people, we are pleased to announce a new interface for Online Coins of the Roman Empire that will aid in the identification of Roman imperial coins by non-specialists (archaeologists and collectors alike). We hope that this will be especially useful for badly worn coins discovered in archaeological excavation. Like the rest of OCRE and other ANS web projects, this interface is responsive to devices of various sizes, making it ideal for use on mobile phones and tablets in the field.

The interface, called "Identify a Coin", is a simplification of  OCRE's browse interface into the basic components that can help to narrow down a coin's visibly identifiable attributes. Selection to specific criteria leads the user into a restricted subset of matches for further comparison (aided by the great number of images associated with coin types provided by partner institutions). For example, a user of this interface can select the type of metal and insert any recognizable characters on either the obverse or reverse legend, with wildcards ('*' characters) designating gaps in legibility. Importantly, the user can select from a nearly complete list of imperial portraits as potential matches. The portraits are listed chronologically, first by dynasty, and then by personage within the dynasty (including empresses and children). In many cases, portrait images are available in gold, silver, and bronze, as well as worn examples that one may encounter with stray finds or excavation. The selection of a material will automatically change the metal of the portraits, when a relevant image is available. More than one material may be chosen, which is useful for later Roman coinage, when severe wear makes it difficult to distinguish between what RIC has designated as "silver," "bronze," or "billon." By clicking the left and right arrows below the image, it is possible to scroll through available portraits, which may show several phases of portraiture, such as Nero, who grew from a teenager into adulthood over the course of his reign.

This interface is one of the most complete depictions of numismatic imperial portraiture, and we hope that it will also prove itself a useful art historical tool to trace the development of Roman portraiture from the Augustan period through the Soldier Emperors to the Tetrarchy until the end of the Roman Empire.

Many thanks to ANS curatorial assistant Disnarda Pinilla for identifying all of the portraits used in this interface. Although primarily drawn from the ANS collection, others are from Berlin, Vienna, or the Fralin Museum at the University of Virginia.

Monday, March 27, 2017

Bibliothèque nationale de France join Nomisma

The Bibliothèque nationale de France (BnF) has joined Nomisma, providing data for more than 2,000 coins of Alexander the Great, Philip III Arrhidaeus, and Lysimachus to PELLA, in time for the Oxford - Paris Alexander Project next week. Since Gallica implements IIIF, I have ingested IIIF image API metadata into Nomisma to make zooming possible. An example can be seen here.

There are now about 20,000 Alexanders in PELLA. With entry of the BnF into the consortium, now five of the most significant collections of ancient coinage contribute Linked Open Data to Nomisma and various related aggregation projects.

Florence Codine provided a concordance spreadsheet of Gallica and PELLA URIs, which I processed with PHP into RDF, extracting additional metadata from OAI-PMH. The script is on Github.

Friday, March 24, 2017

Münzkabinett Vienna joins Nomisma consortium

The Münzkabinett of Vienna is the newest member of the Nomisma consortium, providing data for about 1,500 ancient coins to OCRE, CRRO, and PELLA. Nearly 1,300 of these are Roman Imperial coins, 150 are Roman Republican, and about 100 Alexanders. Vienna is in the early stages of digitization, but it is one of the most significant collections of coins in the world.

The Münzkabinett of the Kunsthistorisches Museum Wien (Vienna in Austria) owns over half a million objects which make it one of the largest collections of its kind, and it can be traced back until the 16th century. It holds coins, medals and banknotes, but also coin dies, bonds and primitive money. Not only does the collection house unique rarities and priceless treasures, its abundance and completeness make it an essential tool for fundamental research in Numismatics and History.

The timing for Vienna's introduction into the numismatic linked open data cloud could not be more perfect. The Oxford-Paris Alexander project is convening in Oxford April 3-4, and so Vienna's entry into PELLA is a demonstration of the growing network of Greek coinage.

Friday, February 17, 2017

Updates and NUDS XSD Schema

At long last, I have made significant updates to the Numismatic Description Schema (NUDS) XSD file, which has been hosted on Github for quite some time. From the documentation:

The Numismatic Description Schema is a codified XML schema based on numismatic database fields proposed by Sebastian Heath and Andrew Meadows. These fields, called the Numismatic Description Standard, are detailed at, and were originally published on The NUDS XML schema is based on this field list and Ethan Gruber's preliminary work mapping coins to Encoded Archival Description, which was detailed in a 2009 Computer Applications in Archaeology paper, "Encoded Archival Description for Numismatic Collections". It is also influenced by the structure of TEI and EAC-CPF, common standards in the Digital Humanities, library, and archival domains. Ideally, a NUDS record should implement XLink attributes to integrate URIs from external Linked Open Data vocabulary systems, such as concepts defined on itself.

The updates have been undertaken to make NUDS more flexible for the encoding of seals for a project overseen by Charlotte Roueche at King's College London. These improvements include documenting every element and attribute in the schema, and enabling the namespacing of EpiDoc TEI into the nuds:description for enhanced prose markup and the nuds:legend for more sophisticated annotation of inscriptions. The Numishare codebase will be extended to include EpiDoc XSLT templates for rendering TEI in the applicable NUDS elements.

Since its inception in summer 2011, the NUDS XML namespace has pointed to, which was never a dereferenceable page. It is now--it is the XSD schema transformed through XSLT into an HTML tag library with usage examples (I am still working on adding these examples).

The XSD is available directly at, which can be considered a stable URL, and may be used for validation of XML files.