Consolidated GeoJSON for Nomisma concepts

For many years, maps on Nomisma.org have shown a map for many types of numismatic concepts. At first, this map was restricted only to showing a single point for a mint, and the eventual adoption of a SPARQL endpoint and aggregation of typological, hoard, and find data enabled the query and display of many types of geographic features associated with a wider variety of concepts. Associated mints, hoards, and individual findspots were requested by Leaflet in three different API calls, and this created some limitations in applying variable styling based on density of distribution after AJAX loading completed while simultaneously binding the layers together in a group to zoom to the full map bounds, since the three API calls may take different amounts of time to respond.

After a few days of work, I have implemented a new singular GeoJSON response that can be accessed via content negotiation for the "application/vnd.geo+json" content type or appending ".geojson" to the concept URI. This singular GeoJSON response is easier to manipulate further after loading, and now both the mints and finds layer display differently sized circles based on the density of objects or types produced or found at a particular geographic location. This makes it much easier to spot the mints that produced the largest volume of coinage for a particular ruler, denomination, etc. The map below illustrates the distribution of mints that produced coinage of Alexander the Great as authority, stated authority, or portrait (the numbers are based on the number of types, not specimens), with Amphipolis and Pella as the mints producing the largest number, unsurprisingly.

Map of Alexander the Great