Pseudo-Demers Cartogram

This is not a true Demers cartogram; it lacks links between adjacent features. Instead of trying to preserve connectedness, this pseudo-cartogram tries to preserve locality, putting each square as close as possible to its origin without overlapping.

forked from mbostock's block: Pseudo-Demers Cartogram

<!DOCTYPE html>
<meta charset="utf-8">
<title>Demers Cartogram</title>
<style>

rect {
  fill: #eee;
  stroke: #000;
  stroke-width: 1.5px;
}

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

// Ratio of Obese (BMI >= 30) in U.S. Adults, CDC 2008
var valueById = [
   NaN, .187, .198,  NaN, .133, .175, .151,  NaN, .100, .125,
  .171,  NaN, .172, .133,  NaN, .108, .142, .167, .201, .175,
  .159, .169, .177, .141, .163, .117, .182, .153, .195, .189,
  .134, .163, .133, .151, .145, .130, .139, .169, .164, .175,
  .135, .152, .169,  NaN, .132, .167, .139, .184, .159, .140,
  .146, .157,  NaN, .139, .183, .160, .143
];

var margin = {top: 0, right: 0, bottom: 0, left: 0},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom,
    padding = 3;

var projection = d3.geo.albersUsa();

var radius = d3.scale.sqrt()
    .domain([0, d3.max(valueById)])
    .range([0, 30]);

var force = d3.layout.force()
    .charge(0)
    .gravity(0)
    .size([width, height]);

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

d3.json("us-state-centroids.json", function(error, states) {
  if (error) throw error;

force
      .nodes(nodes)
      .on("tick", tick)
      .start();

var node = svg.selectAll("rect")
      .data(nodes)
    .enter().append("rect")
      .attr("width", function(d) { return d.r * 2; })
      .attr("height", function(d) { return d.r * 2; });

function tick(e) {
    node.each(gravity(e.alpha * .1))
        .each(collide(.5))
        .attr("x", function(d) { return d.x - d.r; })
        .attr("y", function(d) { return d.y - d.r; });
  }

function gravity(k) {
    return function(d) {
      d.x += (d.x0 - d.x) * k;
      d.y += (d.y0 - d.y) * k;
    };
  }

</script>

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