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Last active September 8, 2023 16:20
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Force-Directed States of America
license: gpl-3.0
redirect: https://observablehq.com/@d3/force-directed-states

Click and drag to move states around.

So, what happens when you use the Delaunay triangulation to compute links between the centroids of the lower 48 United States of America? And then you simulate the whole thing as a force-directed graph? This, it turns out! Built with D3.

<!DOCTYPE html>
<meta charset="utf-8">
<style>
path {
fill: #ddd;
fill-opacity: .8;
stroke: #fff;
stroke-width: 1.5px;
}
line {
stroke: #999;
}
</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(),
force = d3.layout.force().size([width, height]);
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;
var states = topojson.feature(us, us.objects.states),
nodes = [],
links = [];
states.features.forEach(function(d, i) {
if (d.id === 2 || d.id === 15 || d.id === 72) return; // lower 48
var centroid = path.centroid(d);
if (centroid.some(isNaN)) return;
centroid.x = centroid[0];
centroid.y = centroid[1];
centroid.feature = d;
nodes.push(centroid);
});
d3.geom.voronoi().links(nodes).forEach(function(link) {
var dx = link.source.x - link.target.x,
dy = link.source.y - link.target.y;
link.distance = Math.sqrt(dx * dx + dy * dy);
links.push(link);
});
force
.gravity(0)
.nodes(nodes)
.links(links)
.linkDistance(function(d) { return d.distance; })
.start();
var link = svg.selectAll("line")
.data(links)
.enter().append("line")
.attr("x1", function(d) { return d.source.x; })
.attr("y1", function(d) { return d.source.y; })
.attr("x2", function(d) { return d.target.x; })
.attr("y2", function(d) { return d.target.y; });
var node = svg.selectAll("g")
.data(nodes)
.enter().append("g")
.attr("transform", function(d) { return "translate(" + -d.x + "," + -d.y + ")"; })
.call(force.drag)
.append("path")
.attr("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"; })
.attr("d", function(d) { return path(d.feature); });
force.on("tick", function(e) {
link.attr("x1", function(d) { return d.source.x; })
.attr("y1", function(d) { return d.source.y; })
.attr("x2", function(d) { return d.target.x; })
.attr("y2", function(d) { return d.target.y; });
node.attr("transform", function(d) {
return "translate(" + d.x + "," + d.y + ")";
});
});
});
</script>
@jorgeluisyh
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I also tried to replicate it with data of Peru but is not showing, I'm having problems to assign "d" attribute with path(d.feature) to nodes data.

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