"Such a large collection of digital objects lends itself to the potential for meaningful quantitative analysis, including the geographical distribution of coins based on a variety of physical and categorical attributes...Dynamic visualization based on researchers' queries can lead to hypotheses that would have otherwise never been considered."
In other words, allowing for the custom visualization of numismatic data might lead to intuitive leaps in the understanding of history by economists, art historians, classicists and others that both the coins themselves and the data itself would not.
The interface, in the form of a widget set into the Nomisa site, is an open source build, with Apache Solr for the search index, OpenLayers for the display of maps and Ajax to connect the two in a usable interface. Once a coin is entered into Solr, the script Gruber has written checks the numismatic Nomisma ("a collaborative effort to provide stable digital representations of numismatic concepts and entities") to place it geographically.
"OpenLayers then builds its point layer with a KML file generated dynamically from the Solr search results for user's query. A list of facets appears under the map, providing the user with the ability to filter results based on constraints like deity, material, denomination, issuer, and region."
The project is drawing from 400MB of numismatic data, consisting of 560,000 objects. When it launches in mid-March, as a part of the American Numismatics Society's Collections site, it will have close to 200,000 georeferenced objects.
You will be able to search geographically to see what coinage was produced in area mints. You will also have a slider controller that will allow you to fine-tune your searches in terms of time.