A visualization of placename patterns, using data pulled from OpenStreetMap (places), Natural Earth (borders, rivers) and SRTM (elevation).
Originally created to visualize the distribution of places in France ending in -ac, and then the link between German placenames and altitude.
Built at first using SVG, but since this proved too much for Firefox, the visualization now uses canvas (at the expense of nice animations).
Patterns are
Javascript-flavour regular expressions, most importantly '^' and '$' represent name beginning
and end, respectively, so '^ll' matches all placenames which begin with two L's
(many towns in Wales) and 'a$' all placenames which end in A.