Published
Edited
Apr 23, 2021
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chart = {
const links = data.links.map(d => Object.create(d));
const nodes = data.nodes.map(d => Object.create(d));

const simulation = d3
.forceSimulation(nodes)
.force("link", d3.forceLink(links).id(d => d.name))
.force("charge", d3.forceManyBody())
.force("center", d3.forceCenter(width / 2, height / 2))
.force("collision", d3.forceCollide(d => d.degree_1745 + 2));

const svg = d3
.create("svg")
.attr("height", height)
.attr("width", width);

const link = svg
.append("g")
.attr("stroke", "#999")
.attr("stroke-opacity", 0.6)
.selectAll("line")
.data(links)
.join("line")
.attr("stroke-width", d => Math.sqrt(d.value));

const node = svg
.append("g")
.attr("stroke", "#fff")
.attr("stroke-width", 1.5)
.selectAll("circle")
.data(nodes)
.join("circle")
.attr("r", d => d.degree_1745 + 2)
.attr("fill", color)
.on("mouseover", tooltip_in)
.on("mouseout", tooltip_out)
.call(drag(simulation));

simulation.on("tick", () => {
link
.attr("x1", d => d.source.x)
.attr("y1", d => d.source.y)
.attr("x2", d => d.target.x)
.attr("y2", d => d.target.y);

node.attr("cx", d => d.x).attr("cy", d => d.y);
});

return svg.node();
}
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tooltip = d3
.select("body")
.append("div")
.style("position", "absolute")
.style("visibility", "hidden")
.style("background-color", "white")
.attr("class", "tooltip")
// .attr("height", height)
// .attr("width", width)
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tooltip_in = function(event, d) {
return tooltip
.html("<h4>" + d.name + "</h4>")
.style("visibility", "visible")
.style("top", event.pageY + "px")
.style("left", event.pageX + "px");
}
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tooltip_out = function() {
return tooltip
.transition()
.duration(50)
.style("visibility", "hidden");
}
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md`### Get the data file`
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data = FileAttachment("barclay@2.json").json()
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md`### Define height`
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height = 600
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md`### Define the color scale`
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color = {
const scale = d3.scaleOrdinal(d3.schemeCategory10);
return d => scale(d.modularity_class);
}
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md`### Handle dragging`
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drag = simulation => {
function dragstarted(event) {
if (!event.active) simulation.alphaTarget(0.3).restart();
event.subject.fx = event.subject.x;
event.subject.fy = event.subject.y;
}
function dragged(event) {
event.subject.fx = event.x;
event.subject.fy = event.y;
}
function dragended(event) {
if (!event.active) simulation.alphaTarget(0);
event.subject.fx = null;
event.subject.fy = null;
}
return d3.drag()
.on("start", dragstarted)
.on("drag", dragged)
.on("end", dragended);
}
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md`### Include D3`
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d3 = require("d3@6")
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