chart = {
const svg = d3.create("svg")
.attr("viewBox", [0, 0, width, height]);
const {nodes, links} = sankey(data);
svg.append("g")
.attr("stroke", "#000")
.selectAll("rect")
.data(nodes)
.join("rect")
.attr("x", d => d.x0)
.attr("y", d => d.y0)
.attr("height", d => d.y1 - d.y0)
.attr("width", d => d.x1 - d.x0)
.attr("fill", color)
.append("title")
.text(d => `${d.name}\n${format(d.value)}`);
const link = svg.append("g")
.attr("fill", "none")
.attr("stroke-opacity", 0.5)
.selectAll("g")
.data(links)
.join("g")
.style("mix-blend-mode", "multiply");
if (edgeColor === "path") {
const gradient = link.append("linearGradient")
.attr("id", d => (d.uid = DOM.uid("link")).id)
.attr("gradientUnits", "userSpaceOnUse")
.attr("x1", d => d.source.x1)
.attr("x2", d => d.target.x0);
gradient.append("stop")
.attr("offset", "0%")
.attr("stop-color", d => color(d.source));
gradient.append("stop")
.attr("offset", "100%")
.attr("stop-color", d => color(d.target));
}
link.append("path")
.attr("d", d3.sankeyLinkHorizontal())
.attr("stroke", d => edgeColor === "none" ? "#aaa"
: edgeColor === "path" ? d.uid
: edgeColor === "input" ? color(d.source)
: color(d.target))
.attr("stroke-width", d => Math.max(1, d.width));
link.append("title")
.text(d => `${d.source.name} → ${d.target.name}\n${format(d.value)}`);
svg.append("g")
.attr("font-family", "sans-serif")
.attr("font-size", 10)
.selectAll("text")
.data(nodes)
.join("text")
.attr("x", d => d.x0 < width / 2 ? d.x1 + 6 : d.x0 - 6)
.attr("y", d => (d.y1 + d.y0) / 2)
.attr("dy", "0.35em")
.attr("text-anchor", d => d.x0 < width / 2 ? "start" : "end")
.text(d => d.name);
return svg.node();
}
sankey = {
const sankey = d3.sankey()
.nodeId(d => d.name)
.nodeAlign(d3[`sankey${align[0].toUpperCase()}${align.slice(1)}`])
.nodeWidth(15)
.nodePadding(10)
.extent([[1, 5], [width - 1, height - 5]]);
return ({nodes, links}) => sankey({
nodes: nodes.map(d => Object.assign({}, d)),
links: links.map(d => Object.assign({}, d))
});
}
format = {
const format = d3.format(",.0f");
return data.units ? d => `${format(d)} ${data.units}` : format;
}
color = {
const color = d3.scaleDiverging(d3.schemeBuPu);
return d => color(d.category === d3.schemePRGn ? d.name : d.category);
}
data = {
const links = await FileAttachment("energy@2.csv").csv({typed: true});
const nodes = Array.from(new Set(links.flatMap(l => [l.source, l.target])), name => ({name, category: name.replace(/ .*/, "")}));
return {nodes, links, units: "TWh"};
}
width = 954
height = 600
d3 = require("d3@6", "d3-sankey@0.12")
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.
