Building an enclosure diagram

An enclosure diagram is an interesting visualization of hierarchical data structures that uses the recursive circle packing algorithm. It uses containment (nesting) to represent hierarchy. Circles are created for each leaf node in a data tree while its size is proportional to a particular quantitative dimension of each data element. In this recipe, we will learn how to implement this kind of visualization using D3 pack layout.

Getting ready

Open your local copy of the following file in your web browser:

https://github.com/NickQiZhu/d3-cookbook/blob/master/src/chapter9/pack.html

How to do it...

In this recipe, let's see how we can implement an enclosure diagram using d3.layout.pack.

function pack() {
  var _chart = {};

  var _width = 1280, _height = 800,
    _svg,
    _r = 720,
    _x = d3.scale.linear().range([0, _r]),
    _y = d3.scale.linear().range([0, _r]),
    _nodes,
    _bodyG;

  _chart.render = function () {
    if (!_svg) {
      _svg = d3.select("body...