1 // Ratio of Obese (BMI >= 30) in U.S. Adults, CDC 2008
 2 var data = [
 3   , .187, .198, , .133, .175, .151, , .1, .125, .171, , .172, .133, , .108,
 4   .142, .167, .201, .175, .159, .169, .177, .141, .163, .117, .182, .153, .195,
 5   .189, .134, .163, .133, .151, .145, .13, .139, .169, .164, .175, .135, .152,
 6   .169, , .132, .167, .139, .184, .159, .14, .146, .157, , .139, .183, .16, .143
 7 ];
 8 
 9 var svg = d3.select("#chart").append("svg:svg")
10     .attr("width", 960)
11     .attr("height", 500);
12 
13 d3.json("../data/us-states.json", function(json) {
14   var path = d3.geo.path();
15 
16   // A thick black stroke for the exterior.
17   svg.append("svg:g")
18       .attr("class", "black")
19     .selectAll("path")
20       .data(json.features)
21     .enter().append("svg:path")
22       .attr("d", path);
23 
24   // A white overlay to hide interior black strokes.
25   svg.append("svg:g")
26       .attr("class", "white")
27     .selectAll("path")
28       .data(json.features)
29     .enter().append("svg:path")
30       .attr("d", path);
31 
32   // The polygons, scaled!
33   svg.append("svg:g")
34       .attr("class", "grey")
35     .selectAll("path")
36       .data(json.features)
37     .enter().append("svg:path")
38       .attr("transform", function(d) {
39         var centroid = path.centroid(d),
40             x = centroid[0],
41             y = centroid[1];
42         return "translate(" + x + "," + y + ")"
43             + "scale(" + Math.sqrt(data[+d.id] * 5 || 0) + ")"
44             + "translate(" + -x + "," + -y + ")";
45       })
46       .style("stroke-width", function(d) {
47         return 1 / Math.sqrt(data[+d.id] * 5);
48       })
49       .attr("d", path);
50 
51 });