<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8">
<title>U.S. States</title>
<script type="text/javascript" src="../../d3.js"></script>
<script type="text/javascript" src="../../d3.geo.js"></script>
<style type="text/css">
svg {
width: 960px;
height: 500px;
}
#states path, #state-centroids circle {
fill: #ccc;
stroke: #fff;
stroke-width: 1.5px;
}
#state-centroids circle {
fill: steelblue;
fill-opacity: .8;
}
</style>
</head>
<body>
<script type="text/javascript">
// The radius scale for the centroids.
var r = d3.scale.sqrt()
.domain([0, 1e6])
.range([0, 10]);
// Our projection.
var xy = d3.geo.albersUsa();
var svg = d3.select("body").append("svg:svg");
svg.append("svg:g").attr("id", "states");
svg.append("svg:g").attr("id", "state-centroids");
d3.json("../data/us-states.json", function(collection) {
svg.select("#states")
.selectAll("path")
.data(collection.features)
.enter().append("svg:path")
.attr("d", d3.geo.path().projection(xy));
});
d3.json("../data/us-state-centroids.json", function(collection) {
svg.select("#state-centroids")
.selectAll("circle")
.data(collection.features
.sort(function(a, b) { return b.properties.population - a.properties.population; }))
.enter().append("svg:circle")
.attr("transform", function(d) { return "translate(" + xy(d.geometry.coordinates) + ")"; })
.attr("r", 0)
.transition()
.duration(1000)
.delay(function(d, i) { return i * 50; })
.attr("r", function(d) { return r(d.properties.population); });
});
</script>
</body>
</html>