D3 Examples - Weighted nodes and curved links v4

Weighted nodes and curved links v4

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 radius = d3.scaleSqrt()
    .range([0, 6]);
​
var simulation = d3.forceSimulation()
    .force("link", 
           d3.forceLink().id(function(d) { return d.id; })
            .distance(function(d) { return radius(d.source.value / 2) + radius(d.target.value / 2); })
          .strength(function(d) {return 0.75; })
          )
    .force("charge", d3.forceManyBody().strength(-300))
        .force("collide", d3.forceCollide().radius(function(d) { return radius(d.value / 2) + 2; }))
    .force("center", d3.forceCenter(width / 2, height / 2));
​
d3.json("miserables.json", function(error, graph) {
  if (error) throw error;
​
  var link = svg.append("g")
      .attr("class", "links")
    .selectAll("path")
    .data(graph.links)
    .enter().append("svg:path")
      .attr("stroke-width", function(d) { return 1 });
​
  link.style('fill', 'none')
        .style('stroke', 'black')
      .style("stroke-width", '2px');
​
  var node = svg.append("g")
      .attr("class", "nodes")
    .selectAll("g")
    .data(graph.nodes)
    .enter().append("g")
  .style('transform-origin', '50% 50%')
   .call(d3.drag()
          .on("start", dragstarted)
          .on("drag", dragged)
          .on("end", dragended));
  
  node.append('circle')
      .attr("r", function(d) { return radius(d.value / 2); })
      .attr("fill", function(d) { return color(d.group); })
    
  
  node.append("text")
      .attr("dy", ".35em")
      .attr("text-anchor", "middle")
      .text(function(d) { return d.name; });
​
  simulation
      .nodes(graph.nodes)
      .on("tick", ticked);
​
  simulation.force("link")
      .links(graph.links);
​
  function ticked() {
    link.attr("d", function(d) {
        var dx = d.target.x - d.source.x,
            dy = d.target.y - d.source.y,
            dr = Math.sqrt(dx * dx + dy * dy);
        return "M" + 
            d.source.x + "," + 
            d.source.y + "A" + 
            dr + "," + dr + " 0 0,1 " + 
            d.target.x + "," + 
            d.target.y;
    });
​
​
    /*node.selectAll('circle')
        .attr("cx", function(d) { return d.x; })
        .attr("cy", function(d) { return d.y; });*/
    
    node.attr("transform", function(d) { return "translate(" + d.x + "," + 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>
​
    