Radial Line Chart

A radial line chart showing how Twitter's stock has changed over the last year - from July 2016 to July 2017. Not particularly useful - both axes need work to improve legibility (and I'm not sure using d3.extent is a good idea here).

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <script src="d3-scale-radial.js"></script>
  <style>
    text {
      font-size: 14px;
      font-family: monospace;
    }
  </style>
</head>

<body>
  <script>
    var margin = {top: 20, right: 10, bottom: 20, left: 10};
    
    var width = 960 - margin.left - margin.right,
    	height = 500 - margin.top - margin.bottom;
    
    var svg = d3.select("body").append("svg")
    	.attr("width", width + margin.left + margin.right)
      .attr("height", height + margin.top + margin.bottom)
    .append("g")
    	.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
    
    var g = svg.append("g")
    	.attr("transform", "translate(" + width / 2 + "," + height / 2 + ")");
    
    var innerRadius = 100,
        outerRadius = Math.min(width, height) / 2 - 6;
    
    var parseTime = d3.timeParse("%d-%b-%y");
    
    var formatMonth = d3.timeFormat("%b");
    
    var fullCircle = 2 * Math.PI;
    
    var x = d3.scaleTime()
        .range([0, fullCircle]);
    
    var y = d3.scaleRadial()
    		.range([innerRadius, outerRadius]);
    
    var line = d3.lineRadial()
    		.angle(function(d) { return x(d.Date); })
    		.radius(function(d) { return y(d.Close); });
    
    d3.csv("twtr.csv" ,function(d) {
      d.Date = parseTime(d.Date);
      d.Close = +d.Close;
      return d;
    }, function(error, data) {
      if (error) throw error;
      
      x.domain(d3.extent(data, function(d) { return d.Date; }));
  		y.domain(d3.extent(data, function(d) { return d.Close; }));
      
      var linePlot = g.append("path")
      	.datum(data)
        .attr("fill", "none")
        .attr("stroke", "#4099ff")
        .attr("d", line);
      
      var yAxis = g.append("g")
          .attr("text-anchor", "middle");

yTick.append("text")
        .attr("y", function(d) { return -y(d); })
        .attr("dy", "0.35em")
        .text(function(d) { return "$" + d; });
      
      var xAxis = g.append("g");
  
      var xTick = xAxis
        .selectAll("g")
        .data(x.ticks(12))
        .enter().append("g")
          .attr("text-anchor", "middle")
          .attr("transform", function(d) {
            return "rotate(" + ((x(d)) * 180 / Math.PI - 90) + ")translate(" + innerRadius + ",0)";
          });
      
      xTick.append("line")
        .attr("x2", -5)
        .attr("stroke", "#000");

xTick.append("text")
        .attr("transform", function(d) { 
        var angle = x(d);
        return ((angle < Math.PI / 2) || (angle > (Math.PI * 3 / 2))) ? "rotate(90)translate(0,22)" : "rotate(-90)translate(0, -15)"; })
        .text(function(d) { 
          return formatMonth(d);
        })
      	.style("font-size", 10)
      	.attr("opacity", 0.6)
      
      var title = g.append("g")
      		.attr("class", "title")
      		.append("text")
      		.attr("dy", "-0.2em")
      		.attr("text-anchor", "middle")
      		.text("Twitter")
      
      var subtitle = g.append("text")
      		.attr("dy", "1em")
          .attr("text-anchor", "middle")
      		.attr("opacity", 0.6)
      		.text("16/17");  
     	
      var lineLength = linePlot.node().getTotalLength();
      
      linePlot
        .attr("stroke-dasharray", lineLength + " " + lineLength)
        .attr("stroke-dashoffset", -lineLength)
        .transition()
          .duration(2000)
          .ease(d3.easeLinear)
          .attr("stroke-dashoffset", 0);
      
    });
    
  </script>
</body>

https://d3js.org/d3.v4.min.js