Unlisted
Edited
Jun 13, 2023
Paused
20 forks
Importers
20 stars
chart = ChangeLineChart(aapl, {
x: d => d.date,
y: d => d.close,
basis, // e.g., 93.24 (omit for the first y-value)
yLabel: "↑ Change in price (%)",
width,
height: 500,
color: "steelblue"
})
aapl = FileAttachment("aapl.csv").csv({typed: true})
// Copyright 2021 Observable, Inc.
// Released under the ISC license.
// https://observablehq.com/@d3/change-line-chart
function ChangeLineChart(data, {
x = ([x]) => x, // given d in data, returns the (temporal) x-value
y = ([, y]) => y, // given d in data, returns the (quantitative) y-value
basis, // the basis value; defaults to the first y-value
defined, // for gaps in data
curve = d3.curveLinear, // how to interpolate between points
marginTop = 20, // top margin, in pixels
marginRight = 30, // right margin, in pixels
marginBottom = 30, // bottom margin, in pixels
marginLeft = 40, // left margin, in pixels
width = 640, // outer width of chart, in pixels
height = 400, // outer height of chart, in pixels
xType = d3.scaleUtc, // the x-scale type
xDomain, // [xmin, xmax]
xRange = [marginLeft, width - marginRight], // [left, right]
yType = d3.scaleLog, // the y-scale type
yDomain, // [ymin, ymax]
yRange = [height - marginBottom, marginTop], // [bottom, top]
color = "currentColor", // stroke color of line
strokeLinecap = "round", // stroke line cap of the line
strokeLinejoin = "round", // stroke line join of the line
strokeWidth = 1.5, // stroke width of line, in pixels
strokeOpacity = 1, // stroke opacity of line
yFormat = "+~%", // a format specifier string for the y-axis
yLabel // a label for the y-axis
} = {}) {
// Compute values.
const X = d3.map(data, x);
const Y = d3.map(data, y);
const I = d3.range(X.length);
if (defined === undefined) defined = (d, i) => !isNaN(X[i]) && !isNaN(Y[i]);
const D = d3.map(data, defined);
// Normalize the y-values.
if (basis === undefined) basis = Y[0];
Y.forEach((y, i) => Y[i] = y / basis);
// Compute default domains.
if (xDomain === undefined) xDomain = d3.extent(X);
if (yDomain === undefined) yDomain = d3.extent(Y);
// Construct scales and axes.
const xScale = xType(xDomain, xRange);
const yScale = yType(yDomain, yRange);
const xAxis = d3.axisBottom(xScale).ticks(width / 80).tickSizeOuter(0);
const yAxis = d3.axisLeft(yScale).tickFormat((f => d => f(d - 1))(d3.format(yFormat)));
// Construct a line generator.
const line = d3.line()
.defined(i => D[i])
.curve(curve)
.x(i => xScale(X[i]))
.y(i => yScale(Y[i]));
const svg = d3.create("svg")
.attr("width", width)
.attr("height", height)
.attr("viewBox", [0, 0, width, height])
.attr("style", "max-width: 100%; height: auto; height: intrinsic;");
svg.append("g")
.attr("transform", `translate(0,${yScale(1)})`)
.call(xAxis);
svg.append("g")
.attr("transform", `translate(${marginLeft},0)`)
.call(yAxis)
.call(g => g.select(".domain").remove())
.call(g => g.selectAll(".tick line").clone()
.attr("x2", width - marginLeft - marginRight)
.attr("stroke-opacity", 0.1))
.call(g => g.append("text")
.attr("x", -marginLeft)
.attr("y", 10)
.attr("fill", "currentColor")
.attr("text-anchor", "start")
.text(yLabel));
svg.append("path")
.attr("fill", "none")
.attr("stroke", color)
.attr("stroke-width", strokeWidth)
.attr("stroke-linecap", strokeLinecap)
.attr("stroke-linejoin", strokeLinejoin)
.attr("stroke-opacity", strokeOpacity)
.attr("d", line(I));
return svg.node();
}
import {howto, altplot} from "@d3/example-components"
One platform to build and deploy the best data apps
Experiment and prototype by building visualizations in live JavaScript notebooks. Collaborate with your team and decide which concepts to build out.
Use Observable Framework to build data apps locally. Use data loaders to build in any language or library, including Python, SQL, and R.
Seamlessly deploy to Observable. Test before you ship, use automatic deploy-on-commit, and ensure your projects are always up-to-date.