d3mapping.js

<script>
var width = 1500;
var height = 1500;
var color = d3.scale.linear()
	    .domain([0, 350000])
	    .range(["white", "#3498db"]);

var div = d3.select("body").append("div")
            .attr("class", "tooltip")
	    .style("opacity", 0.8);

var format = d3.format(".0%")

//Create an SVG element for us to use.
var svg = d3.select("body").append("svg").attr("width", width).attr("height", height);
 
d3.json("statgeo.json", function(uk){

//Gets the coordinate data from our dataset.
    var subunits = topojson.feature(uk, uk.objects.thenewestdict1);

   //Allows us to check the validity of our data in the console.
    console.log(subunits);

    //Creates a projection which we can apply to the path.
    var projection = d3.geo.mercator()
    .center([-0.10,51.5171])
    .rotate([0,0])
    .scale(95000)
    .translate([width / 2, height / 3]);

    var path = d3.geo.path().projection(projection);

    svg.append("g")
    .attr("class", "boroughs")
    .selectAll("path")
    .data(topojson.feature(uk, uk.objects.thenewestdict1).features)
    .enter().append("path")
    .attr("d", path)
    .attr("id", function(d){return d.properties.Name})
    .attr("fill", function(d){return color(d.properties.population)})
    .attr("stroke", "black")
    .attr("stroke-width", "0.35");

    svg.selectAll("path")
    .data(topojson.feature(uk, uk.objects.thenewestdict1).features)
    .on("mouseover", function(d){div.transition().duration(200); 
    div.html("<b>" + d.properties.Name  + "</b><br>" 
    + "Population: " + d.properties.population + "<br>" +
    "Average house price: £" + d.properties.avghouseprice + "<br>"
    + "Percent renting from landlord: " + d.properties.percentrent + "<br>"
   + "New homes built 2011/2012: " + d.properties.numnewhomes + "<br>" + 
    "People per new home built: " + d3.round(d.properties.peoplepernewhome))});
    });
	</script>

londonhousing.py

import csv, json, os

boroughmetrics = {}

geojson = json.load(open('clean.json'))
csvdata = csv.reader(open('london-borough-profiles.csv', 'U'))

csvdata.next() #Skip headers.

for line in csvdata:
  tempdict = {}
	csvname = line[0]
	tempdict = {'population': int(line[1]), 
				'avghouseprice': int(line[2]), 
				'numnewhomes': int(line[3]), 
				'percentrent': float(line[4]),
				'peoplepernewhome': float(line[1]) / int(line[3])}

	for borough in geojson['objects']['thenewestdict1']['geometries']:
		boroughname = borough['properties']['Name']
		if csvname == boroughname:
			borough['properties'].update(tempdict)

with open('statgeo.json', 'w') as outfile:
	json.dump(geojson, outfile)

os.system("topojson -o stattopo.json statgeo.json -p")