Using d3-tile to display raster image tiles underneath some TopoJSON vectors, and d3-zoom for pan & zoom.
Tiles copyright OpenStreetMap contributors.
forked from mbostock's block: Raster & Vector II
forked from saifulazfar's block: Raster & Vector
https://d3js.org/d3.v4.min.js
https://d3js.org/d3-tile.v0.0.min.js
https://d3js.org/topojson.v1.min.js