Pedigree Tree

A variation on the elbow dendrogram, though using the tree layout. A couple notes: a custom separation function is used so that the distance between sets of parents is half the distance between parents themselves; the tree layout draws the leaf nodes at the right extreme of the layout, so a large right margin is used to inset the leaf nodes; the leaf nodes also have a custom path (d.target.children is null).

In response to a Stack Overflow question.

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

text {
  font-family: "Helvetica Neue", Helvetica, sans-serif;
}

.name {
  font-weight: bold;
}

.about {
  fill: #777;
  font-size: smaller;
}

.link {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}

</style>
<body>
<script src="//d3js.org/d3.v3.min.js"></script>
<script>

var margin = {top: 0, right: 320, bottom: 0, left: 0},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

var tree = d3.layout.tree()
    .separation(function(a, b) { return a.parent === b.parent ? 1 : .5; })
    .children(function(d) { return d.parents; })
    .size([height, width]);

var svg = d3.select("body").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 + ")");

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

var nodes = tree.nodes(json);

var link = svg.selectAll(".link")
      .data(tree.links(nodes))
    .enter().append("path")
      .attr("class", "link")
      .attr("d", elbow);

var node = svg.selectAll(".node")
      .data(nodes)
    .enter().append("g")
      .attr("class", "node")
      .attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; })

node.append("text")
      .attr("class", "name")
      .attr("x", 8)
      .attr("y", -6)
      .text(function(d) { return d.name; });

node.append("text")
      .attr("x", 8)
      .attr("y", 8)
      .attr("dy", ".71em")
      .attr("class", "about lifespan")
      .text(function(d) { return d.born + "–" + d.died; });

node.append("text")
      .attr("x", 8)
      .attr("y", 8)
      .attr("dy", "1.86em")
      .attr("class", "about location")
      .text(function(d) { return d.location; });
});

function elbow(d, i) {
  return "M" + d.source.y + "," + d.source.x
       + "H" + d.target.y + "V" + d.target.x
       + (d.target.children ? "" : "h" + margin.right);
}

</script>

https://d3js.org/d3.v3.min.js