Tuesday, June 20, 2017

Experimenting with 3D integration in OCRE

The Wild West of 3D Capture in Cultural Heritage

The lowered technical barriers and costs of 3D capture (especially photogrammetry) within the museum and archaeology domains has seen an explosion of 3D data within the cultural heritage sector. The Smithsonian X 3D and British Museum (led by Nomisma scientific committee member, Dan Pett) endeavors are among the best recognized efforts in this area, but 3D cultural heritage models (from artifact scans to excavation trenches and entire sites) are being published to the web by many organizations through a wide variety of information systems. Many organizations have turned to Sketchfab as the primary mode of publication, but others are using home-grown systems. In truth, 3D publication is the wild west. There aren't even readily agreed-upon open standards for the models themselves, let alone metadata standards, publication frameworks or APIs for accessing models/metadata (in contrast to 2D images through IIIF standardization).

As such, integration of 3D data back into the scholarly research ecosystem has fallen very far behind 3D production capacity. We have seen that Sketchfab models can be embedded into web-based news articles or blogs (such as the Telegraph article above or Sarah Bond's recent post on Forbes), which have been an excellent medium for making these resources available to a general audience. However, we cannot overlook the fact that these are also valuable resources to a scholarly audience, and this audience isn't going to poke around various universities' institutional repositories or Sketchfab profiles for relevant 3D data. Numismatists studying Roman imperial coinage use Online Coins of the Roman Empire, and if there are 3D models of Roman coins, they should expect to access that material through OCRE and not Sketchfab directly. The same goes for Greek pottery experts and Kerameikos.org. Scholars more broadly interested in the ancient world may access 3D objects through Pelagios and more general audiences (both academic and public) may interact with these objects through Europeana or DPLA.

I have high hopes that the 3D GLAM community (including commercial entities such as Sketchfab) will move toward open standards for the dissemination of these data. Taking Greek pottery as an example, 3D models are much preferred over 2D photography for viewing inscriptions and iconography, and if 3D models can be annotated following the same standards we see in IIIF (Open Annotation RDF), scholars will be able to view all objects depicting Dionysus, regardless of the 2D/3D medium of capture.

Sketchfab models in OCRE, a Proof of Concept

The coin cabinet of Heinrich-Heine-Universität Düsseldorf, a Nomisma partner through the NUMiD network of German university coin cabinets, recently uploaded three models to Sketchfab: a Roman provincial coin showing the damnatio memoriae of Geta, an imperial coin of Severus Alexander (RIC IV 455), and an imperial coin of Constantine (RIC VII Constantinople 126). The latter two coins have already been integrated into OCRE, and so I set forth on the task of incorporating triples for the 3D models into the RDF for these two coins.

Fortunately, two librarians at the University of South Florida, Xiying Mi and Bonita Pollock, have put forth a useful proposal at ALA (see Linked Metadata for 3D-Models: From Dublin Core to Europeana Data Model) to capture some basic 3D model metadata and associate this information with the cultural heritage object.

Since we have already implemented the IIIF extension for the Europeana Data Model in Nomisma, it was fairly straightfoward to link to a 3D model in much the same manner by using the edm:isShownBy property to link to the Sketchfab URI, which is cast as an edm:WebResource class. This edm:WebResource carries some additional metadata about the model itself, including the capture process (photogrammetry as a dcterms:format linking to a Getty AAT URI, etc.).

A 3D model of a coin of Severus Alexander, shown in OCRE
These data model adaptations were followed by some updates to Numishare's underlying SPARQL query and UI scripts to render the 3D model, when available. There is a conditional within the Javascript to use an iframe to embed the Sketchfab model when the edm:WebResource is a Sketchfab URI. So far, there's only one condition for rendering. Ultimately, the scripts will read the mime-type from the RDF metadata and use an open source JS 3D library accordingly (such as Universal Viewer).

This of course is predicated on the cultural heritage community coming to an agreement on open standards for 3D models and APIs for accessing these models and associated metadata. In this endeavor, I see myself as a consumer of 3D--not for my own research purposes, but as a technical developer building middleware for scholars to access the models to achieve their needs. In my role as a consumer, I hope to be able to steer the content producers and architects of 3D information systems onto a path that results in the greatest potential for reuse and synthesis.

Thursday, June 8, 2017

Updates to symbol/monogram pages in OCRE

I have just pushed some changes to symbol and monogram pages in OCRE, which are more broadly applied to Numishare. Up to this point, we have published several dozen late Roman monograms from RIC 10 and a small handful of Siscia Officina marks from RIC 8. The data underlying these symbols are in RDF, conforming to the Nomisma ontology and data model. The web pages displayed little more than a list of metadata about the symbol, but no further context. Altogether, these pages weren't particularly useful as scholarly tools.

Map of Marcian monogram 1

Following updates to Nomisma, I have implemented two new features on symbol pages:

  1. A map showing the distribution of mints and findspots (a heatmap layer showing all findspots and individual layers for finds and hoards). The geoJSON APIs in Nomisma were extended to support SPARQL queries for geographic data by passing a 'symbol' request parameter. See http://nomisma.org/apis#getMints, for example.
  2. A list of coin types that bear these symbols, with available images, when available. The list of types is downloadable as CSV, and the user can click a button to view the underlying SPARQL query, which could be copied, modified, and submitted directly to Nomisma's endpoint (see below).

Coin types that show Marcian monogram 1

Below is the SPARQL query for getting a list of types associated with a monogram, with some basic metadata:

SELECT ?type ?label ?startDate ?endDate ?mint ?mintLabel ?den ?denLabel WHERE {
    SELECT ?side WHERE {
     ?side nmo:hasMonogram <%URI%>
?type ?prop ?side
   MINUS {?type dcterms:isReplacedBy ?replaced}
   ?type a nmo:TypeSeriesItem ;
   skos:prefLabel ?label FILTER(langMatches(lang(?label), "en")) .
   OPTIONAL {?type nmo:hasStartDate ?startDate}
   OPTIONAL {?type nmo:hasEndDate ?endDate}
   OPTIONAL {?type nmo:hasMint ?mint . 
    ?mint skos:prefLabel ?mintLabel 
       FILTER(langMatches(lang(?mintLabel), "en"))}
   OPTIONAL {?type nmo:hasDenomination ?den . 
    ?den skos:prefLabel ?denLabel 
       FILTER(langMatches(lang(?denLabel), "en"))}

Since these features are now inherent to Numishare, they will be available for the enormous array of Greek monograms that will be published as part of the Hellenistic Royal Coinages project. I hope to have a prototype of a few monograms published in PELLA within the next few weeks.

As more and more Nomisma partners adopt IIIF, these monogram URIs will form a basis for image annotation, and eventually these symbol pages will use Open Annotation and IIIF APIs to display photographic examples of monograms, in addition to a print and web-ready idealized SVG renderings.

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, http://nomisma.org/research/metrical.

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 Nomisma.org 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": "http://numismatics.org/chrr/id/ME2",
      "geometry": {
        "type": "Point",
        "coordinates": [
      "when": {
        "timespans": [
            "start": "-0038",
            "end": "-0038"
      "properties": {
        "toponym": "Albaredo d'Adige (Italy)",
        "gazetteer_label": "Albaredo d'Adige (Italy)",
        "gazetteer_uri": "http://www.geonames.org/3183350/",
        "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 Nomisma.org. 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 <http://www.kenom.de/>.

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 Nomisma.org 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 http://www.greekcoinage.org/nuds.html, and were originally published on Nomisma.org. 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 Nomisma.org 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 http://nomisma.org/nuds, 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 http://nomisma.org/nuds.xsd, which can be considered a stable URL, and may be used for validation of XML files.

Tuesday, February 14, 2017

Roman coins from the Metropolitan Museum of Art enter Nomisma

The Met Museum is the latest institution to be integrated into the Linked Ancient World Data Initiative, following their major announcement last week concerning the release of more than 375,000 images into the public domain and the publication of a dump of their data into a massive CSV file.

Aureus of Julius Caesar in CRRO

I almost immediately got to work on parsing this CSV in order to link their coins to Online Coins of the Roman Empire and Coinage of the Roman Republic Online, but found that the dumps did not include full type references to RIC or RRC, nor did I find a clear way of extracting images from the database for re-use. With many thanks to curator Christopher Lightfoot for providing a concordance between the Met's coins and reference numbers and Ben Rasmusen for some tips on interacting with the Met's not-yet-published 'additionalImages' web service, I wrote a simple PHP script to generate Nomisma-compliant RDF. I have just ingested this into Nomisma's SPARQL endpoint. About 60 coins have been positively linked to URIs in CRRO and OCRE. Furthermore, these coins will be integrated into the Pelagios Project by means of the Nomisma->Pelagios export feature.

You can see examples of three aurei of Julius Caesar (RRC 466/1) from the Met along with examples of the same type from six other museums. You can get a concordance list of Met and coin type URIs back out of the SPARQL endpoint with the following query: https://gist.github.com/ewg118/f9c8bae782fdc841af6c7aca782ef06d.

Monday, February 13, 2017

OCRE surpasses 100,000 physical specimens, including Polish coin finds, and more

We have several additional news events to report:

  1. We have finally published the Roman coins from the American Numismatic Society with references to RIC 9 to Online Coins of the Roman Empire. This has brought us to a milestone 100,000 physical specimens linked to about 42,000 imperial types spanning five centuries from Augustus to Zeno.
  2. We have reprocessed our data from RIC 4 in order to represent the type-subtype hierarchy within that volume more accurately. Some data errors have been fixed due PHP processing glitches or typos in deity names.
  3. More than 7,200 coins in the Finds of Roman Coins in Poland project (part of the European Coin Find Network umbrella) have been ingested into Nomisma.org for query and visualization. Of these coins, 23 are linked to URIs defined by OCRE.
  4. I discovered a glitch in my script for mapping references to Price (1991) to IDs in Pella, and now about 500 coins in the ANS of Philip III and Lysimachus have been added into Pella.
  5. Berlin has added an export for Macedonian coins found in the excavations of Priene, and two have been added into Pella.

OCRE has eclipsed 100,000 coins, but our total between this, CRRO, Pella, and AoD stands at about 153,000.

Wednesday, February 8, 2017

Harvard Art Museums coins reprocessed, added as IIIF contributors

Harvard Art Museums is one of three contributors of coins to Nomisma.org, providing data and images for all three of our major coin type projects: OCRE, CRRO, and Pella. They are also one of our few partners providing images according to IIIF image API specifications. Following the application of the Europeana Data Model specs for IIIF integration for Rutgers' entry into Nomisma.org, I have updated my script for harvesting numismatic content from Harvard to include IIIF manifest metadata.

Accordingly, I made some minor code changes in Numishare to handle IIIF manifests for combined images (obverse and reverse in the same image file). You can see an example of a Philip III coin from Harvard here.

The Harvard Art Museums' coins in Pella will be the perfect test cases for applying Open Annotation + IIIF for annotating symbols and monograms defined by URIs in the Online Greek Corpus project.

Thursday, January 5, 2017

Rutgers University's Badian Collection added to CRRO + IIIF support

Rutgers University's Badian Collection is the newest contributor to Nomisma.org, providing 682 Roman Republican coins to Coinage of the Roman Republic Online. The Rutgers University Libraries are the publishers of these data, and by means of their Fedora repository software and IIIF APIs, I was able to write a PHP script to harvest their MODS/XML (and other miscellaneous metadata records) and generate Nomisma-compliant RDF.

Following recent updates to Kerameikos.org's IIIF integration, I implemented the same modifications to Nomisma's RDF model: data objects for describing IIIF images and services according to Europeana Data Model specifications. The Nomisma documentation has been updated accordingly: http://nomisma.org/documentation/contribute#iiif.

The user interfaces in Numishare (and therefore CRRO) have been updated to optionally query for the dcterms:isReferencedBy property associated with examples of coin types. I have implemented the IIIF plugin for Leaflet to display the zoomable image in a Fancybox popup window. See the Rutgers coin on http://numismatics.org/crro/id/rrc-474.2b, for example. Several other partners have implemented IIIF, and I will reprocess these collections to add service metadata into their RDF dumps. It is on the ANS agenda for 2017 to deploy our own IIIF image server. In the coming years, it is my aim to implement an image annotation system that will make it easier to identify and tag symbols and iconographic attributes on coinage, which will facilitate a wider range of art historical or political/economic analyses of coins.