Marimekko Chart

A Marimekko Chart, inspired by Freakalytics. Thanks to Noah Iliinsky for the suggestion. Jason Davies has published an even-simpler interactive implementation using the “slice-dice” treemap layout algorithm!

<!DOCTYPE html>
<meta charset="utf-8">
<title>Marimekko Chart</title>
<style>

body {
  font: 10px sans-serif;
}

rect {
  stroke: #000;
}

svg {
  shape-rendering: crispEdges;
}

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

var width = 960,
    height = 500,
    margin = 20;

var x = d3.scale.linear()
    .range([0, width - 3 * margin]);

var y = d3.scale.linear()
    .range([0, height - 2 * margin]);

var z = d3.scale.category10();

var n = d3.format(",d"),
    p = d3.format("%");

var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height)
  .append("g")
    .attr("transform", "translate(" + 2 * margin + "," + margin + ")");

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

var offset = 0;

// Nest values by segment. We assume each segment+market is unique.
  var segments = d3.nest()
      .key(function(d) { return d.segment; })
      .entries(data);

// Compute the total sum, the per-segment sum, and the per-market offset.
  // You can use reduce rather than reduceRight to reverse the ordering.
  // We also record a reference to the parent segment for each market.
  var sum = segments.reduce(function(v, p) {
    return (p.offset = v) + (p.sum = p.values.reduceRight(function(v, d) {
      d.parent = p;
      return (d.offset = v) + d.value;
    }, 0));
  }, 0);

// Add x-axis ticks.
  var xtick = svg.selectAll(".x")
      .data(x.ticks(10))
    .enter().append("g")
      .attr("class", "x")
      .attr("transform", function(d) { return "translate(" + x(d) + "," + y(1) + ")"; });

xtick.append("line")
      .attr("y2", 6)
      .style("stroke", "#000");

xtick.append("text")
      .attr("y", 8)
      .attr("text-anchor", "middle")
      .attr("dy", ".71em")
      .text(p);

// Add y-axis ticks.
  var ytick = svg.selectAll(".y")
      .data(y.ticks(10))
    .enter().append("g")
      .attr("class", "y")
      .attr("transform", function(d) { return "translate(0," + y(1 - d) + ")"; });

ytick.append("line")
      .attr("x1", -6)
      .style("stroke", "#000");

ytick.append("text")
      .attr("x", -8)
      .attr("text-anchor", "end")
      .attr("dy", ".35em")
      .text(p);

// Add a group for each segment.
  var segments = svg.selectAll(".segment")
      .data(segments)
    .enter().append("g")
      .attr("class", "segment")
      .attr("xlink:title", function(d) { return d.key; })
      .attr("transform", function(d) { return "translate(" + x(d.offset / sum) + ")"; });

// Add a rect for each market.
  var markets = segments.selectAll(".market")
      .data(function(d) { return d.values; })
    .enter().append("a")
      .attr("class", "market")
      .attr("xlink:title", function(d) { return d.market + " " + d.parent.key + ": " + n(d.value); })
    .append("rect")
      .attr("y", function(d) { return y(d.offset / d.parent.sum); })
      .attr("height", function(d) { return y(d.value / d.parent.sum); })
      .attr("width", function(d) { return x(d.parent.sum / sum); })
      .style("fill", function(d) { return z(d.market); });
});

</script>

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