Published
Edited
Aug 25, 2020
8 forks
4 stars
chart = {
const svg = d3.create("svg")
.attr("viewBox", [0, 0, width, height]);
// Positive values
svg.append("g")
.attr("fill", color)
.selectAll("rect")
.data(data.map(d => d.value > 0 ? d : {value: 0}))
.join("rect")
.attr("x", (d, i) => x(i))
.attr("y", d => y(d.value))
.attr("height", d => y(0) - y(d.value))
.attr("width", x.bandwidth());
// Negative values
svg.append("g")
.attr("fill", 'hsl(0, 80%, 60%)') // red, but just not too bright
.selectAll("rect")
.data(data.map(d => d.value < 0 ? d : {value: 0}))
.join("rect")
.attr("x", (d, i) => x(i))
.attr("y", d => y(0))
.attr("height", d => y(0) - y(-d.value))
.attr("width", x.bandwidth());
svg.append("g")
.call(xAxisPos);
svg.append("g")
.call(xAxisNeg);
svg.append("g")
.call(yAxis);
return svg.node();
}
data = {
// Load, clean, and sort the data
let sortedData = Object.assign(d3.csvParse(await FileAttachment("alphabet.csv").text(), ({letter, frequency}) => ({name: letter, value: +frequency})).sort((a, b) => d3.descending(a.value, b.value)), {format: "%", y: "↑ Frequency"})
// Randomly flip some values (from positive to negative)
sortedData.forEach(v => (Math.random() > 0.5) ? (v.value *= -1.0) : '')
return sortedData
}
x = d3.scaleBand()
.domain(d3.range(data.length))
.range([margin.left, width - margin.right])
.padding(0.1)
y = {
// Find the largest absolute value
const absMax = d3.max(data, d => Math.abs(d.value))
// Use that for the scale
return d3.scaleLinear()
.domain([-absMax, absMax]).nice()
.range([height - margin.bottom, margin.top])
}
xAxisPos = g => g
.attr("transform", `translate(0,${height / 2})`)
.call(d3.axisBottom(x).tickFormat(i => data[i].name).tickSizeOuter(0))
.selectAll('g.tick')
.attr('display', i => data[i].value < 0 ? 'none' : '')
xAxisNeg = g => g
.attr("transform", `translate(0,${height / 2})`)
.call(d3.axisTop(x).tickFormat(i => data[i].name).tickSizeOuter(0))
.selectAll('g.tick')
.attr('display', i => data[i].value > 0 ? 'none' : '')
yAxis = g => g
.attr("transform", `translate(${margin.left},0)`)
.call(d3.axisLeft(y).ticks(null, data.format))
.call(g => g.select(".domain").remove())
.call(g => g.append("text")
.attr("x", -margin.left)
.attr("y", 10)
.attr("fill", "currentColor")
.attr("text-anchor", "start")
.text(data.y))
color = "steelblue"
height = 500
margin = ({top: 30, right: 0, bottom: 30, left: 40})
d3 = require("d3@5")
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.
