Lovecraft’s letters geo-located. Sadly it’s “one-record, one map point”, rather than the some vast seething tentacular web of points and connections. Still, the database wranglers appear to have done the basic work, parsing the structured records / list published by the Providence-based archives. Thus it may be possible to get just the Lovecraft data out, and then have software make it into a visual map. The correspondence.ie Web site does have visualisations, but I couldn’t spot one on the list for Lovecraft.
A simpler and more creative task would be an artistic wall-chart map showing all his known correspondents, with a uniformly hand-drawn portrait of each (if their appearance is known). The size of the portrait would indicate the size / duration / importance of the correspondence. With small arrows to indicate any notable non-Lovecraft correspondence with other members of the Circle. With insets on the map to cover New York City, California, the British Isles and the British Empire, etc. In fact, such a big wall-map might be a nice incentive to boost sales of the forthcoming mega-index covering all of Lovecraft’s letters.