Radar Chart (Football Manager)

I have always been a huge fan of those radar/spider chart in football manager player's statistics page.

<!DOCTYPE html>
<meta charset="utf-8">
<style>

body {
  font: 12px sans-serif;
}

</style>
<body>
<script src="https://d3js.org/d3.v3.min.js"></script>
<script>

var width = 960,
    height = 500,
    barHeight = height / 2 - 40;

var color = d3.scale.ordinal()
    .range(["#9eb36f", "#cadd9e", "#eee9a6", "#e3bf6b", "#c87572"]);

var tickValues = [4,8,12,16,20];

var svg = d3.select('body').append("svg")
    .attr("width", width)
    .attr("height", height)
  .append("g")
    .attr("transform", "translate(" + width/2 + "," + height/2 + ")");

d3.json("data.json", function(error, data) {

var numBars = data.data.length;

var radius = d3.scale.linear()
      .domain([0,20])
      .range([0, barHeight]);

var line = d3.svg.line.radial()
    .interpolate("linear-closed")
    .radius(function(d) { return radius(d.count); })
    .angle(function(d,i) { return (i * 2 * Math.PI / numBars); });

var area = d3.svg.area.radial()
    .interpolate(line.interpolate())
    .innerRadius(radius(0))
    .outerRadius(line.radius())
    .angle(line.angle());

tickValues.sort(function(a,b) { return b - a; });

lines.append("line")
    .attr("y2", - barHeight )
    .style("stroke", "#5e5e5e")
    .style("stroke-width",".5px")
    .attr("transform", function(d, i) { return "rotate(" + (i * 360 / numBars) + ")"; });

lines.append("text")
    .attr("class", "names")
    .attr("x", function(d, i) { return (barHeight + 15) * Math.sin((i * 2 * Math.PI / numBars)); })
    .attr("y", function(d, i) { return -(barHeight + 15) * Math.cos((i * 2 * Math.PI / numBars)); })
    .attr("text-anchor", function(d,i) { 
    if (i===0 || i===numBars/2) {
        return "middle";
      }else if (i <= numBars/2) {
        return "begin";
      }else {
        return "end";
      }
    })
    .style("font-weight","bold")
    .text(function(d) { return d.skill; });

layer = svg.selectAll(".layer")
    .data([data]).enter()
    .append("path")
    .attr("class", "layer")
    .attr("d", function(d) { return area(d.data); })
    .attr("fill", "none")
    .attr("stroke", "black")
    .attr("stroke-width", "2px");

});

</script>

https://d3js.org/d3.v3.min.js