This is a map that uses [leaflet.js](http://leafletjs.com/) and [d3.js](http://d3js.org/) in a way that combines the two so that the d3.js object zooms and pans with the map. It is as used as an example in the book [D3 Tips and Tricks](https://leanpub.com/D3-Tips-and-Tricks).

It is derived from the Mike Bostock [tutorial on Leaflet](http://bost.ocks.org/mike/leaflet/) but is simplified somewhat.