index.html

## index.html
<!DOCTYPE html>
<html class="ocks-org">
<meta charset="utf-8">
<title>Sankey Diagram</title>
<base href="http://bost.ocks.org/mike/sankey/" target="_blank">

<style>

@import url(../style.css?aea6f0a);

#chart {
  height: 900px;
}

.node rect {
  cursor: move;
  fill-opacity: .9;
  shape-rendering: crispEdges;
}

.node text {
  pointer-events: none;
  text-shadow: 0 1px 0 #fff;
}

.link {
  fill: none;
  stroke: #000;
  stroke-opacity: .2;
}

.link:hover {
  stroke-opacity: .5;
}

</style>
<body>


<h1>Sankey Diagrams</h1>

<p id="chart">

<aside>Drag to rearrange nodes.</aside>

<!-- <p class="attribution">Source: <a href="http://www.decc.gov.uk/en/content/cms/tackling/2050/calculator_on/calculator_on.aspx">Department of Energy & Climate Change</a>, <a href="http://tamc.github.com/Sankey/">Tom Counsell</a>. -->

<aside>Sankey diagrams are closely related to <a href="http://en.wikipedia.org/wiki/Alluvial_diagram">alluvial diagrams</a>, which show how network structure changes over time.</aside>


<p>Thanks to Mike Bostock, whose <a href="http://bost.ocks.org/mike/sankey/">D3 Sankey plugin</a> was used to help build this visualisation.</p>

<footer>
  <aside>November 25, 2013</aside>
  <a  rel="author">Dan Wood</a>
</footer>

<script src="http://d3js.org/d3.v2.min.js?2.9.1"></script>
<script src="sankey.js"></script>
<script>

var margin = {top: 1, right: 1, bottom: 6, left: 1},
    width = 960 - margin.left - margin.right,
    height = 900 - margin.top - margin.bottom;

var formatNumber = d3.format(",.3r"),
    format = function(d) { return formatNumber(d) + " TWh"; },
    color = d3.scale.category20();

var svg = d3.select("#chart").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 sankey = d3.sankey()
    .nodeWidth(15)
    .nodePadding(20)
    .size([width, height]);

var path = sankey.link();

d3.json("https://gist.github.com/DanielJWood/7751118/raw/fa750bcc148c705303b84e4eb831acbebfee403a/sankey.json", function(energy) {

  sankey
      .nodes(energy.nodes)
      .links(energy.links)
      .layout(32);

  var link = svg.append("g").selectAll(".link")
      .data(energy.links)
    .enter().append("path")
      .attr("class", "link")
      .attr("d", path)
          //Define with of stroke of link based whatever is larger, d.dy or 1
      .style("stroke-width", function(d) { return Math.max(1, d.dy); })
      .sort(function(a, b) { return b.dy - a.dy; });

  link.append("p")
      .text(function(d) { return d.source.name + " → " + d.target.name + "\n" + format(d.value); })
      .attr("x", -6)
      .attr("y", function(d) { return d.dy / 2; })
      .attr("dy", ".35em");

  var node = svg.append("g").selectAll(".node")
      .data(energy.nodes)
    .enter().append("g")
      .attr("class", "node")
      .attr("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"; })
    .call(d3.behavior.drag()
      .origin(function(d) { return d; })
      .on("dragstart", function() { this.parentNode.appendChild(this); })
      .on("drag", dragmove));

  node.append("rect")
      .attr("height", function(d) { return d.dy; })
      .attr("width", sankey.nodeWidth())
      .style("fill", function(d) { return d.color = color(d.name.replace(/ .*/, "")); })
      .style("stroke", function(d) { return d3.rgb(d.color).darker(2); })
    .append("title")
      .text(function(d) { return d.name + "\n" + format(d.value); });

  node.append("text")
      .attr("x", -6)
      .attr("y", function(d) { return d.dy / 2; })
      .attr("dy", ".35em")
      .attr("text-anchor", "end")
      .attr("transform", null)
      .text(function(d) { return d.name; })
    .filter(function(d) { return d.x < width / 2; })
      .attr("x", 6 + sankey.nodeWidth())
      .attr("text-anchor", "start");

  function dragmove(d) {
    d3.select(this).attr("transform", "translate(" + d.x + "," + (d.y = Math.max(0, Math.min(height - d.dy, d3.event.y))) + ")");
    sankey.relayout();
    link.attr("d", path);
  }
});

</script>