Published
Edited
Jul 15, 2020
chart = {
const svg = d3.create("svg")
.attr("viewBox", [0, 0, 975, 610]);
svg.append("path")
.datum(topojson.feature(us, us.objects.nation))
.attr("fill", "#ddd")
.attr("d", path);
svg.append("path")
.datum(topojson.mesh(us, us.objects.states, (a, b) => a !== b))
.attr("fill", "none")
.attr("stroke", "black")
.attr("stroke-linejoin", "round")
.attr("d", path);
const legend = svg.append("g")
.attr("fill", "#000")
.attr("transform", "translate(915,608)")
.attr("text-anchor", "middle")
.style("font", "10px sans-serif")
.selectAll("g")
.data(radius.ticks(4).slice(1))
.join("g");
legend.append("circle")
.attr("fill", "none")
.attr("stroke", "#fff")
.attr("cy", d => -radius(d))
.attr("r", radius);
legend.append("text")
.attr("y", d => -2 * radius(d))
.attr("dy", "1.3em")
.text(radius.tickFormat(4, "s"));
svg.append("g")
.attr("fill", "blue")
.attr("fill-opacity", 0.5)
.attr("stroke", "#fff")
.attr("stroke-width", 0.5)
.selectAll("circle")
.data(data
.filter(d => d.position)
.sort((a, b) => d3.descending(a.value, b.value)))
.join("circle")
.attr("transform", d => `translate(${d.position})`)
.attr("r", d => radius(d.value))
.append("title")
.text(d => `${d.title}
${format(d.value)}`);
return svg.node();
}
data = (await FileAttachment("population.json").json()).slice(1).map(([population, state, county]) => {
const id = state + county;
const feature = features.get(id);
return {
id,
position: feature && path.centroid(feature),
title: feature && feature.properties.name,
value: +population
};
})
radius = d3.scaleSqrt([0, d3.max(data, d => d.value)], [0, 40])
features = new Map(topojson.feature(us, us.objects.counties).features.map(d => [d.id, d]))
path = d3.geoPath()
format = d3.format(",.0f")
us = FileAttachment("counties-albers-10m.json").json()
topojson = require("topojson-client@3")
d3 = require("d3@5", "d3-array@2")
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.
