block by syntagmatic 3754357

Fracturing California

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The data is random. If you refresh the page it will change.

A prototype for irresponsible election day metaphors of a country torn apart by the two party system, based on Jim Vallandingham’s Visualizing The Racial Divide.

Learn why gerrymandering undermines democracy.

113th US Congressional Voting Districts provided by Len De Groot.

index.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>California fractured by congressional district</title>
<style>
path.district {
  stroke: #fff;
  stroke-width: 1px;
  stroke-opacity: 0.3;
}
text {
  font-size: 24px;
}
</style>
<svg width="960" height="500"></svg>
<script src="//d3js.org/d3.v2.js"></script>
<script>
var selected_district = "CA";

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

var color = d3.scale.linear()
  .domain([0,0.5,1])
  .range(["#d7191c", "#ddd", "#2c7bb6"])
  .interpolate(d3.interpolateLab);

var projection = d3.geo.azimuthal()
  .mode("equidistant")
  .origin([-118, 37])
  .scale(2400)
  .translate([480, 260]);

var force = d3.layout.force()
  .size([960, 500]);

var nodes = [],
    links = [];

var path = d3.geo.path()
  .projection(projection);

d3.json("113-ca.json", function(collection) {
  // visible districts
  var selected = collection.features
    .filter(function(district) {
      return district.properties.UID.indexOf(selected_district) > -1;
    })

  selected
    .forEach(function(d) {
      centroid = path.centroid(d);
      centroid.x = centroid[0];
      centroid.y = centroid[1];
      centroid.feature = d;
      centroid.tract_data = Math.random();
      nodes.push(centroid);
    });

  d3.geom.delaunay(nodes).forEach(function(d) {
    links.push(edge(d[0], d[1]));
    links.push(edge(d[1], d[2]));
    links.push(edge(d[2], d[0]));
  });

  /*
  link = svg.selectAll("line")
      .data(links)
    .enter().append("svg:line")
      .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; })
      .attr("stroke", "#777")
      .attr("stroke-opacity", "0.3")
      .attr("stroke-width", "1")
      */

  node = svg.selectAll("g")
    .data(nodes)
  .enter().append("svg:g")
    .attr("transform", function(d) { return "translate(" + (-d.x) + "," + (-d.y) + ")"})
  .append("path")
    .attr("class", "district")
    .attr("fill", function(d) { return color(d.tract_data); })
    .attr("transform", function(d) { return "translate(" + (d.x) + "," + (d.y) + ")"})
    .attr("d", function(d) { return path(d.feature) })

  svg.append("text")
    .attr({
      "id": "district",
      "x": 220,
      "y": 420,
    });

  var tick_count = 0;

  force
    .gravity(0.0)
    .nodes(nodes)
    .links(links)
    .linkDistance( function(d) { return d.distance })
    .charge(-0.6)
    .friction(0.4)
    .theta(0.9)

  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("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"});
  });

  setTimeout(force.start, 1500) ;
});

function edge(a,b) {
  var dx = a.x - b.x,
      dy = a.y - b.y,
      diff = 22 * Math.abs(a.tract_data - b.tract_data);

  var distance = Math.sqrt(dx * dx + dy * dy) + diff;
  return {
    source: a,
    target: b,
    distance: distance
  }
};
</script>