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@mbostock mbostock/.block
Last active Mar 1, 2019

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Albers Equal-Area Conic
license: gpl-3.0
redirect: https://observablehq.com/@d3/conic-equal-area
<!DOCTYPE html>
<meta charset="utf-8">
<style>
.graticule {
fill: none;
stroke: #777;
stroke-width: .5px;
stroke-opacity: .5;
}
.land {
fill: #222;
}
.county-boundary {
fill: none;
stroke: #fff;
stroke-width: .5px;
}
.state-boundary {
fill: none;
stroke: #fff;
}
</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 projection = d3.geo.albers()
.rotate([96, 0])
.center([-.6, 38.7])
.parallels([29.5, 45.5])
.scale(1070)
.translate([width / 2, height / 2])
.precision(.1);
var path = d3.geo.path()
.projection(projection);
var graticule = d3.geo.graticule()
.extent([[-98 - 45, 38 - 45], [-98 + 45, 38 + 45]])
.step([5, 5]);
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
svg.append("path")
.datum(graticule)
.attr("class", "graticule")
.attr("d", path);
d3.json("/mbostock/raw/4090846/us.json", function(error, us) {
if (error) throw error;
svg.insert("path", ".graticule")
.datum(topojson.feature(us, us.objects.land))
.attr("class", "land")
.attr("d", path);
svg.insert("path", ".graticule")
.datum(topojson.mesh(us, us.objects.counties, function(a, b) { return a !== b && !(a.id / 1000 ^ b.id / 1000); }))
.attr("class", "county-boundary")
.attr("d", path);
svg.insert("path", ".graticule")
.datum(topojson.mesh(us, us.objects.states, function(a, b) { return a !== b; }))
.attr("class", "state-boundary")
.attr("d", path);
});
d3.select(self.frameElement).style("height", height + "px");
</script>
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