D3 Examples - Sankey with circles

Sankey with circles

This is an example of a Sankey diagram made using d3.js and the sankey plugin.

It has a point of differenc from other Sankey diagrams I have seen in that the nodes can be moved horizontally and vertically.

A description of how it was put together and techniques for implimenting Sankey diagrams in general with d3.js can be found at d3noob.org or you can download the full text in the D3 Tips and Tricks book (for free) from Leanpub.

The data is sourced from the World Resources Institute (http://www.wri.org/chart/world-greenhouse-gas-emissions-2005). Open in full window for full effect.

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<!DOCTYPE html>
<meta charset="utf-8">
<title>SANKEY Experiment</title>
<style>
 
.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>
 
<p id="chart">
 
<script src="https://d3js.org/d3.v3.js"></script>
<script src="sankey.js"></script>
<script>
  
var units = "Widgets";
 
var margin = {top: 10, right: 10, bottom: 10, left: 10},
    width = 1200 - margin.left - margin.right,
    height = 740 - margin.top - margin.bottom;
 
var formatNumber = d3.format(",.0f"),    // zero decimal places
    format = function(d) { return formatNumber(d) + " " + units; },
    color = d3.scale.category20();
 
// append the svg canvas to the page
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 + ")");
 
// Set the sankey diagram properties
var sankey = d3.sankey()
    .nodeWidth(36)
    .nodePadding(10)
    .size([width, height]);
 
var path = d3.svg.diagonal()
    .source(function(d) {
        return {"x":d.source.y + d.source.dy / 2,
                "y":d.source.x + sankey.nodeWidth()/2};
    })            
    .target(function(d) {
        return {"x":d.target.y + d.target.dy / 2,
                "y":d.target.x + sankey.nodeWidth()/2};
    })
    .projection(function(d) { return [d.y, d.x]; });
​
 
// load the data (using the timelyportfolio csv method)
d3.csv("ivrHops.csv", function(error, data) {
​
  //set up graph in same style as original example but empty
  graph = {"nodes" : [], "links" : []};
​
    data.forEach(function (d) {
      graph.nodes.push({ "name": d.curr_state_name });
      graph.nodes.push({ "name": d.next_state_name });
      graph.links.push({ "source": d.source,
                         "target": d.next_state_name,
                         "value": +d.call_flow });
     });
​
     // return only the distinct / unique nodes
     graph.nodes = d3.keys(d3.nest()
       .key(function (d) { return d.name; })
       .map(graph.nodes));
​
     // loop through each link replacing the text with its index from node
     graph.links.forEach(function (d, i) {
       graph.links[i].source = graph.nodes.indexOf(graph.links[i].source);
       graph.links[i].target = graph.nodes.indexOf(graph.links[i].target);
     });
​
     //now loop through each nodes to make nodes an array of objects
     // rather than an array of strings
     graph.nodes.forEach(function (d, i) {
       graph.nodes[i] = { "name": d };
     });
​
 
  sankey
      .nodes(graph.nodes)
      .links(graph.links)
      .layout(32);
 
// add in the links
  var link = svg.append("g").selectAll(".link")
      .data(graph.links)
    .enter().append("path")
      .attr("class", "link")
      .attr("d", path)
      .style("stroke-width", function(d) { return Math.max(1, Math.sqrt(d.dy)); })
      .sort(function(a, b) { return b.dy - a.dy; });
 
// add the link titles
  link.append("title")
        .text(function(d) {
        return d.source.name + " → " + 
                d.target.name + "\n" + format(d.value); });
 
// add in the nodes
  var node = svg.append("g").selectAll(".node")
      .data(graph.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));
 
// add the rectangles for the nodes
//  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); });
 
    // add the circles for the nodes
    node.append("circle")
        .attr("cx", sankey.nodeWidth()/2)
        .attr("cy", function (d) {
            return d.dy/2;
        })
        .attr("r", function (d) {
            return Math.sqrt(d.dy);
        })
      .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); });
  
  // add in the title for the nodes
  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");
 
// the function for moving the nodes
  function dragmove(d) {
    d3.select(this).attr("transform", 
        "translate(" + (
               d.x = Math.max(0, Math.min(width - d.dx, d3.event.x))
            ) + "," + (
                   d.y = Math.max(0, Math.min(height - d.dy, d3.event.y))
            ) + ")");
    sankey.relayout();
    link.attr("d", path);
  }
});
 
</script>
 
</body>
</html>
    