More than 4000 monograms published to Nomisma

After a tremendous amount of work over the last year or more, just over 4,000 monograms that appear on Greek coinages have been published as unambiguous URIs on Nomisma.org. These monograms constitute a combination of symbols that appear on Hellenistic Royals Coinages (HRC) and Corpus Nummorum (CN). Using Computer Vision methodologies employed by Karsten Tolle, identical monograms were matched across datasets, reducing the number of monograms published by both projects from 4,500 to 4,000. The potential matches were vetted by Peter van Alfen and Ulrike Peter. The monogram URIs in HRC and Corpus Nummorum have been integrated as skos:exactMatch properties in Nomisma, making it possible to create UNION SPARQL queries that enable the querying of types (and associated Nomisma concepts) across these disparate projects. This is a huge advancement in our ability to study Greek monograms and their meaning on coinage. Even in Hellenistic Royal Coinages, we did not have the time in the first phase of the project to disambiguate identical monograms across PELLA, SCO, and PCO, which limited the data and geographic visualization of monograms within their own typological silos. 

The user interfaces in Nomisma.org have been extended to include many of the features for symbols in the Numishare platform which publishes HRC: 

• The Nomisma.org browse page can be filtered to display results only for the http://nomisma.org/symbol/ namespace, and once this filter is active, a user can refine the search results by Greek and Latin (or other) letters which appear within the monogram. It is possible to switch to a grid view that makes viewing monograms more intuitive. If constituent letters have been selected, it is possible to display a map in a popup window that contains the mints, hoards, and individual finds associated with the monogram.
  

The Nomisma.org browse page showing monograms that consist of several Greek letters.

• The page for each monogram will show associated mints, hoard, and findspots. The size of the mint points vary by the number of types that produced the monogram.
• The page will show a network graph rendered in d3 showing the relationship between that monogram and other monograms that appear on associated coin types. By default, the network graph shows the most immediate relationships, but it is possible to click another button to view the secondary relationships.

The distribution map and network graph of Monogram 1830, uniting different Hellenistic typologies.

• A list of types (and photographic examples, if available) will appear. The type list is downloadable as CSV and sortable by several categories. 
• The SVG graphics associated with each monogram are in the Public Domain and can be reused for both commercial and noncommercial publication.
  

It should be noted that although thousands of monograms from CN have been published and integrated into Nomisma, we have yet to reindex the coin type data from CN that includes their own monogram URIs. As a result, the data visualizations and type lists in Nomisma only reflect HRC. Corpus Nummorum type data will be reingested into Nomisma's SPARQL endpoint in the near future.

After publishing the RDF derived from the HRC and CN monogram data, the network graph query is formed by querying a monogram of a particular URI (or its skos:exactMatches) which appear on the obverse or reverse of a type, and extending those type queries by including other monogram URIs will appear on those same types (filtering for matches that conform to the Nomisma symbol concept scheme).

SELECT ?symbol ?altSymbol ?image ?altImage WHERE {
  BIND (<http://nomisma.org/symbol/monogram.01830> as ?symbol)
  {?side nmo:hasControlmark ?symbol}
  UNION {?side nmo:hasControlmark ?match .
    ?match ^skos:exactMatch ?symbol}
  ?type nmo:hasObverse|nmo:hasReverse ?side .
  {?side nmo:hasControlmark ?altSymbol}
  UNION {?side nmo:hasControlmark ?altMatch .
  ?altMatch ^skos:exactMatch ?altSymbol }
      FILTER (?altSymbol != ?symbol 
        && contains(str(?altSymbol), "http://nomisma.org/symbol"))  
  ?symbol crm:P165i_is_incorporated_in ?image .
  ?altSymbol crm:P165i_is_incorporated_in ?altImage .
} 

Such queries can be extended to list mints or authorities which produced them, and how many types in total are associated with those concepts. By associating types with Nomisma concepts for denominations, materials, mints, individual rulers or broader political organizations, it is possible to query and visualize relationships between entities in complex ways that simply could not be undertaken before applying Linked Open Data principles to numismatics.

Once the Corpus Nummorum data have been updated in Nomisma, I will prepare a second post discussing more complex use cases with mints and authorities.