Force-Directed Network Graph

This is a Force-Directed Graph based on mbostock's example: /mbostock/4062045 The data in the graph was taken from http://snap.stanford.edu/data/p2p-Gnutella08.html and contains A sequence of snapshots of the Gnutella peer-to-peer file sharing network from August 2002.

The graph is showing only the first few hundred connections. That is why some of the points are left alone, because it is a partial picture of the data. The data was divided into ~10 groups of close by points. Each group is shown with different colors.

<!DOCTYPE html>
<meta charset="utf-8">
<style>

.node {
  stroke: #fff;
  stroke-width: 1.5px;
}

.link {
  stroke: #999;
  stroke-opacity: .6;
}

</style>
<body>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
<script>

var width = 960,
    height = 600;

var color = d3.scale.category20();

var force = d3.layout.force()
    .charge(-30)
    .linkDistance(10)
    .size([width, height]);

var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height);

d3.json("data.json", function(error, graph) {
  if (error) throw error;

force
      .nodes(graph.nodes)
      .links(graph.links)
      .start();

var link = svg.selectAll(".link")
      .data(graph.links)
    .enter().append("line")
      .attr("class", "link")
      .style("stroke-width", function(d) { return Math.sqrt(d.value); });

var node = svg.selectAll(".node")
      .data(graph.nodes)
    .enter().append("circle")
      .attr("class", "node")
      .attr("r", 5)
      .style("fill", function(d) { return color(d.group); })
      .call(force.drag);

node.append("title")
      .text(function(d) { return d.name; });

force.on("tick", function() {
    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; });
  });
});

</script>

https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js