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Last active March 8, 2017 11:39
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Area Choropleth
license: gpl-3.0

This choropleth encodes the area of each county using color on a log scale from red to blue.

<!DOCTYPE html>
<meta charset="utf-8">
<style>
.states {
fill: none;
stroke: #fff;
stroke-linejoin: round;
}
</style>
<body>
<script src="//d3js.org/d3.v3.min.js"></script>
<script src="//d3js.org/topojson.v1.min.js"></script>
<script>
var width = 960,
height = 500;
var fill = d3.scale.log()
.domain([10, 500])
.range(["brown", "steelblue"]);
var path = d3.geo.path();
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
d3.json("/mbostock/raw/4090846/us.json", function(error, us) {
if (error) throw error;
svg.append("g")
.attr("class", "counties")
.selectAll("path")
.data(topojson.feature(us, us.objects.counties).features)
.enter().append("path")
.attr("d", path)
.style("fill", function(d) { return fill(path.area(d)); });
svg.append("path")
.datum(topojson.mesh(us, us.objects.states, function(a, b) { return a.id !== b.id; }))
.attr("class", "states")
.attr("d", path);
});
</script>
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