Data and Digital Storytelling Lead @ 360info.org, hosted by Monash University. ❤️ making things for fun and for social good!
chart = PieChart(population, {
name: d => d.name,
value: d => d.value,
width,
height: 500,
suffix: " people"
})
population = FileAttachment("population-by-age.csv").csv({typed: true})
// Copyright 2018-2023 Observable, Inc.
// Released under the ISC license.
// https://observablehq.com/@d3/pie-chart
function PieChart(data, {
name = ([x]) => x, // given d in data, returns the (ordinal) label
value = ([, y]) => y, // given d in data, returns the (quantitative) value
title, // given d in data, returns the title text
width = 640, // outer width, in pixels
height = 400, // outer height, in pixels
innerRadius = 0, // inner radius of pie, in pixels (non-zero for donut)
outerRadius = Math.min(width, height) / 2, // outer radius of pie, in pixels
labelRadius = (innerRadius * 0.2 + outerRadius * 0.8), // center radius of labels
format = ",", // a format specifier for values (in the label)
suffix = "", // a string to put after the formatted value
names, // array of names (the domain of the color scale)
colors, // array of colors for names
stroke = innerRadius > 0 ? "none" : "white", // stroke separating widths
strokeWidth = 1, // width of stroke separating wedges
strokeLinejoin = "round", // line join of stroke separating wedges
padAngle = stroke === "none" ? 1 / outerRadius : 0, // angular separation between wedges, in radians
} = {}) {
// Compute values.
const N = d3.map(data, name);
const V = d3.map(data, value);
const I = d3.range(N.length).filter(i => !isNaN(V[i]));
// Unique the names.
if (names === undefined) names = N;
names = new d3.InternSet(names);
// Chose a default color scheme based on cardinality.
if (colors === undefined) colors = d3.schemeSpectral[names.size];
if (colors === undefined) colors = d3.quantize(t => d3.interpolateSpectral(t * 0.8 + 0.1), names.size);
// Construct scales.
const color = d3.scaleOrdinal(names, colors);
// Compute titles.
if (title === undefined) {
const formatValue = d3.format(format);
title = i => `${N[i]}\n${formatValue(V[i])}${suffix}`;
} else {
const O = d3.map(data, d => d);
const T = title;
title = i => T(O[i], i, data);
}
// Construct arcs.
const arcs = d3.pie().padAngle(padAngle).sort(null).value(i => V[i])(I);
const arc = d3.arc().innerRadius(innerRadius).outerRadius(outerRadius);
const arcLabel = d3.arc().innerRadius(labelRadius).outerRadius(labelRadius);
const svg = d3.create("svg")
.attr("width", width)
.attr("height", height)
.attr("viewBox", [-width / 2, -height / 2, width, height])
.attr("style", "max-width: 100%; height: auto; height: intrinsic;");
svg.append("g")
.attr("stroke", stroke)
.attr("stroke-width", strokeWidth)
.attr("stroke-linejoin", strokeLinejoin)
.selectAll("path")
.data(arcs)
.join("path")
.attr("fill", d => color(N[d.data]))
.attr("d", arc)
.append("title")
.text(d => title(d.data));
svg.append("g")
.attr("font-family", "sans-serif")
.attr("font-size", 10)
.attr("text-anchor", "middle")
.selectAll("text")
.data(arcs)
.join("text")
.attr("transform", d => `translate(${arcLabel.centroid(d)})`)
.selectAll("tspan")
.data(d => {
const lines = `${title(d.data)}`.split(/\n/);
return (d.endAngle - d.startAngle) > 0.25 ? lines : lines.slice(0, 1);
})
.join("tspan")
.attr("x", 0)
.attr("y", (_, i) => `${i * 1.1}em`)
.attr("font-weight", (_, i) => i ? null : "bold")
.text(d => d);
return Object.assign(svg.node(), {scales: {color}});
}
import {howto} from "@d3/example-components"
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.
