We need to project our map data as well as scaling and centering it so it fits in our viewport.

scale.js

// Values to centre and scale the map of Toronto.
var x = -14100
var y = 7300
var scale = 66700

// Define map projection.
projection = d3.geo.albers().translate([x, y]).scale([scale])

// Define path generator.
var path = d3.geo.path().projection(projection);