This symbol map encodes the area of each county using a circle at the county's centroid.
forked from mbostock's block: County Circles
license: gpl-3.0 |
This symbol map encodes the area of each county using a circle at the county's centroid.
forked from mbostock's block: County Circles
<!DOCTYPE html> | |
<meta charset="utf-8"> | |
<style> | |
circle { | |
fill: none; | |
stroke: steelblue; | |
} | |
</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 path = d3.geo.path(); | |
var svg = d3.select("body").append("svg") | |
.attr("width", width) | |
.attr("height", height); | |
d3.json("https://gist.githubusercontent.com/mbostock/4090846/raw/d534aba169207548a8a3d670c9c2cc719ff05c47/us.json", function(error, us) { | |
if (error) throw error; | |
svg.selectAll("circle") | |
.data(topojson.feature(us, us.objects.counties).features) | |
.enter().append("circle") | |
.attr("transform", function(d) { return "translate(" + path.centroid(d) + ")"; }) | |
.attr("r", function(d) { return Math.sqrt(path.area(d) / Math.PI); }); | |
}); | |
</script> |