tutorial/8/index.html

<!DOCTYPE html>
<html lang="en">
<head>
  <title>Maptime AMS #4: Geopolitics, Borders &amp; D3.js!</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
  <script src="http://d3js.org/d3.v3.min.js" charset="utf-8"></script>
  <script src="http://d3js.org/topojson.v1.min.js"></script>
  <style>
    * {
      margin: 0;
      padding: 0;
    }

    svg {
      position: absolute;
      width: 100%;
      height: 100%;
    }

    path {
      stroke: #666;
      fill: none;
      fill-opacity: 0.6;
      stroke-width: 1px;
      stroke-linecap: round;
      stroke-linejoin: round;
    }

    #boundary path {
      stroke-dasharray: 3, 5;
    }
  </style>
</head>
<body>
  <svg>
    <g id="boundary"></g>
    <g id="states"></g>
  </svg>
  <h1>United States in <span id="year">1790</span></h1>
  <script>
    var svgStates = d3.select("svg #states"),
        svgBoundary = d3.select("svg #boundary"),
        states = {},
        startYear = 1790,
        currentYear = startYear;

    var width = window.innerWidth,
        height = window.innerHeight;

    var projection = d3.geo.albersUsa()
        .translate([width / 2, height / 2]);

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

    d3.json("../../data/usa.json", function(error, boundary) {
      svgBoundary.selectAll("path")
          .data(boundary.features)
          .enter()
        .append("path")
          .attr("d", path)
    });

    d3.json("../../data/states.json", function(error, topologies) {

      for (var i = 0; i < topologies.length; i++) {
        states[startYear + i * 10] = topojson.feature(topologies[i], topologies[i].objects.stdin);
      }

      function update() {
        svgStates.selectAll("path")
            .data(states[currentYear].features)
            .enter()
          .append("path")
            .attr("d", path);
      }

      update();
    });
  </script>
</body>
</html>