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@mbostock
Last active February 26, 2019 22:33
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Tobler–Mercator
license: gpl-3.0
height: 960
border: no
redirect: https://observablehq.com/@d3/tobler-mercator
<!DOCTYPE html>
<meta charset="utf-8">
<style>
.stroke {
fill: none;
stroke: #000;
stroke-width: 3px;
}
.fill {
fill: #fff;
}
.graticule {
fill: none;
stroke: #777;
stroke-width: 0.5px;
stroke-opacity: 0.5;
}
.land {
fill: #222;
}
.boundary {
fill: none;
stroke: #fff;
stroke-width: 0.5px;
}
</style>
<svg width="960" height="960"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script src="https://unpkg.com/topojson-client@3"></script>
<script>
var svg = d3.select("svg"),
width = +svg.attr("width"),
height = +svg.attr("height");
var projection = d3.geoProjection(toblerMercatorRaw)
.scale((width - 3) / (2 * Math.PI))
.translate([width / 2, height / 2])
.precision(0.1);
var path = d3.geoPath()
.projection(projection);
var graticule = d3.geoGraticule();
svg.append("defs").append("path")
.datum(graticule.outline())
.attr("id", "sphere")
.attr("d", path);
svg.append("use")
.attr("class", "stroke")
.attr("xlink:href", "#sphere");
svg.append("use")
.attr("class", "fill")
.attr("xlink:href", "#sphere");
svg.append("path")
.datum(graticule)
.attr("class", "graticule")
.attr("d", path);
d3.json("https://unpkg.com/world-atlas@1/world/50m.json", function(error, world) {
if (error) throw error;
svg.insert("path", ".graticule")
.datum(topojson.feature(world, world.objects.land))
.attr("class", "land")
.attr("d", path);
svg.insert("path", ".graticule")
.datum(topojson.mesh(world, world.objects.countries, function(a, b) { return a !== b; }))
.attr("class", "boundary")
.attr("d", path);
});
function toblerMercatorRaw(lambda, phi) {
var cosPhi = Math.cos(phi);
return [lambda * cosPhi * cosPhi, Math.log(Math.tan((Math.PI / 2 + phi) / 2))];
}
</script>
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