selection // brush an axis below to see this update!
viewof selection = {
// Specify the chart’s dimensions.
const width = 928;
const height = keys.length * 120;
const marginTop = 20;
const marginRight = 10;
const marginBottom = 20;
const marginLeft = 10;
// Create an horizontal (*x*) scale for each key.
const x = new Map(Array.from(keys, key => [key, d3.scaleLinear(d3.extent(data, d => d[key]), [marginLeft, width - marginRight])]));
// Create the vertical (*y*) scale.
const y = d3.scalePoint(keys, [marginTop, height - marginBottom]);
// Create the color scale.
const color = d3.scaleSequential(x.get(keyz).domain(), t => d3.interpolateBrBG(1 - t));
// Create the SVG container.
const svg = d3.create("svg")
.attr("viewBox", [0, 0, width, height])
.attr("width", width)
.attr("height", height)
.attr("style", "max-width: 100%; height: auto;");
// Append the lines.
const line = d3.line()
.defined(([, value]) => value != null)
.x(([key, value]) => x.get(key)(value))
.y(([key]) => y(key));
const path = svg.append("g")
.attr("fill", "none")
.attr("stroke-width", 1.5)
.attr("stroke-opacity", 0.4)
.selectAll("path")
.data(data.slice().sort((a, b) => d3.ascending(a[keyz], b[keyz])))
.join("path")
.attr("stroke", d => color(d[keyz]))
.attr("d", d => line(d3.cross(keys, [d], (key, d) => [key, d[key]])))
.call(path => path.append("title")
.text(d => d.name));
// Append the axis for each key.
const axes = svg.append("g")
.selectAll("g")
.data(keys)
.join("g")
.attr("transform", d => `translate(0,${y(d)})`)
.each(function(d) { d3.select(this).call(d3.axisBottom(x.get(d))); })
.call(g => g.append("text")
.attr("x", marginLeft)
.attr("y", -6)
.attr("text-anchor", "start")
.attr("fill", "currentColor")
.text(d => d))
.call(g => g.selectAll("text")
.clone(true).lower()
.attr("fill", "none")
.attr("stroke-width", 5)
.attr("stroke-linejoin", "round")
.attr("stroke", "white"));
// Create the brush behavior.
const deselectedColor = "#ddd";
const brushHeight = 50;
const brush = d3.brushX()
.extent([
[marginLeft, -(brushHeight / 2)],
[width - marginRight, brushHeight / 2]
])
.on("start brush end", brushed);
axes.call(brush);
const selections = new Map();
function brushed({selection}, key) {
if (selection === null) selections.delete(key);
else selections.set(key, selection.map(x.get(key).invert));
const selected = [];
path.each(function(d) {
const active = Array.from(selections).every(([key, [min, max]]) => d[key] >= min && d[key] <= max);
d3.select(this).style("stroke", active ? color(d[keyz]) : deselectedColor);
if (active) {
d3.select(this).raise();
selected.push(d);
}
});
svg.property("value", selected).dispatch("input");
}
return Object.assign(svg.property("value", data).node(), {scales: {color}});
}
data = FileAttachment("cars.csv").csv({typed: true})
keys = data.columns.slice(1)
import {legend as Legend} from "@d3/color-legend"
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.
