chart = {
const root = tree(data);
const svg = d3.create("svg");
svg.append("g")
.attr("fill", "none")
.attr("stroke", "#555")
.attr("stroke-opacity", 0.4)
.attr("stroke-width", 1.5)
.selectAll("path")
.data(root.links())
.join("path")
.attr("d", d => `
M${d.target.y},${d.target.x}
C${d.source.y + root.dy / 2},${d.target.x}
${d.source.y + root.dy / 2},${d.source.x}
${d.source.y},${d.source.x}
`);
svg.append("g")
.selectAll("circle")
.data(root.descendants())
.join("circle")
.attr("cx", d => d.y)
.attr("cy", d => d.x)
.attr("fill", d => d.children ? "#555" : "#999")
.attr("r", 2.5);
svg.append("g")
.attr("font-family", "sans-serif")
.attr("font-size", 10)
.attr("stroke-linejoin", "round")
.attr("stroke-width", 3)
.selectAll("text")
.data(root.descendants())
.join("text")
.attr("x", d => d.y)
.attr("y", d => d.x)
.attr("dy", "0.31em")
.attr("dx", d => d.children ? -6 : 6)
.text(d => d.data.name)
.filter(d => d.children)
.attr("text-anchor", "end")
.clone(true).lower()
.attr("stroke", "white");
return svg.attr("viewBox", autoBox).node();
}
function autoBox() {
document.body.appendChild(this);
const {x, y, width, height} = this.getBBox();
document.body.removeChild(this);
return [x, y, width, height];
}
data = FileAttachment("states-counties.json").json()
tree = data => {
const root = d3.hierarchy(data).sort((a, b) => d3.descending(a.height, b.height) || d3.ascending(a.data.name, b.data.name));
root.dx = 10;
root.dy = width / (root.height + 1);
return d3.cluster().nodeSize([root.dx, root.dy])(root);
}
d3 = require("d3@6")
Purpose-built for displays of data
Observable is your go-to platform for exploring data and creating expressive data visualizations. Use reactive JavaScript notebooks for prototyping and a collaborative canvas for visual data exploration and dashboard creation.
