D3 Examples - Force-Directed Graph from Flow CSV

Force-Directed Graph from Flow CSV

This simple force-directed graph shows character co-occurence in Les Misérables. A physical simulation of charged particles and springs places related characters in closer proximity, while unrelated characters are farther apart. Layout algorithm inspired by Tim Dwyer and Thomas Jakobsen. Data based on character coappearence in Victor Hugo's Les Misérables, compiled by Donald Knuth.

Compare this display to a force layout with curved links, a force layout with fisheye distortion and a matrix diagram.

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<!DOCTYPE html>
<meta charset="utf-8">
<style>
​
.links line {
  stroke: #999;
  stroke-opacity: 0.6;
}
​
.nodes circle {
  stroke: #fff;
  stroke-width: 1.5px;
}
​
</style>
<svg width="960" height="600"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>
​
var svg = d3.select("svg"),
    width = +svg.attr("width"),
    height = +svg.attr("height");
​
var color = d3.scaleOrdinal(d3.schemeCategory20);
​
var simulation = d3.forceSimulation()
    .force("link", d3.forceLink().id(function(d) { return d.id; }))
    .force("charge", d3.forceManyBody())
    .force("center", d3.forceCenter(width / 2, height / 2));
​
d3.csv("unhcr_popstats_asylum_2016-top2.csv", function(error, data) {
  if (error) throw error;
  
  console.log(data);
  
  var graph = {};
  graph.links = [];
​
  var nodesByName = {};
  function nodeByNameFinder(name) {
    return nodesByName[name] || (nodesByName[name] = {id: name});
  }
​
  data.forEach((flow) => {
    var link = {};
    // Create nodes for each unique source and target.
    link.source = nodeByNameFinder(flow.Origin);
    link.target = nodeByNameFinder(flow.CountryOfAsylum);
    link.value = Number(flow.Value);
    graph.links.push(link);
  });
  
  console.log(graph.links);
  // Extract the array of nodes from the map by name.
  graph.nodes = d3.values(nodesByName);
  console.log(graph.nodes);
//});
  
//d3.json("miserables.json", function(error, graph) {
//  if (error) throw error;
  
  var widthScale = d3.scaleSqrt()
    .domain(d3.extent(graph.links.map((d) => d.value)))
    .range([1, 9]);
  
  var link = svg.append("g")
      .attr("class", "links")
    .selectAll("line")
    .data(graph.links)
    .enter().append("line")
      .attr("stroke-width", (d) => widthScale(d.value));
​
  var node = svg.append("g")
      .attr("class", "nodes")
    .selectAll("circle")
    .data(graph.nodes)
    .enter().append("circle")
      .attr("r", 5)
      .attr("fill", function(d) { return color(d.group); })
      .call(d3.drag()
          .on("start", dragstarted)
          .on("drag", dragged)
          .on("end", dragended));
​
  node.append("title")
      .text(function(d) { return d.id; });
​
  simulation
      .nodes(graph.nodes)
      .on("tick", ticked);
​
  simulation.force("link")
      .links(graph.links);
​
  function ticked() {
    link
        .attr("x1", function(d) { return d.source.x; })
        .attr("y1", function(d) { return d.source.y; })
        .attr("x2", function(d) { return d.target.x; })
        .attr("y2", function(d) { return d.target.y; });
​
    node
        .attr("cx", function(d) { return d.x; })
        .attr("cy", function(d) { return d.y; });
  }
});
​
function dragstarted(d) {
  if (!d3.event.active) simulation.alphaTarget(0.3).restart();
  d.fx = d.x;
  d.fy = d.y;
}
​
function dragged(d) {
  d.fx = d3.event.x;
  d.fy = d3.event.y;
}
​
function dragended(d) {
  if (!d3.event.active) simulation.alphaTarget(0);
  d.fx = null;
  d.fy = null;
}
​
</script>
​
    