In this course, you will learn to create your own interactive data visualizations for the web with D3.js, a very popular JavaScript library. 

Starting with the fundamentals, you'll learn about SVG, selections, classes, and styles, as well as displaying data. This will give you the base to start working with more advanced concepts. 

Once you’ve got the basics out of the way, you will start practicing drawing various scatter plots, where you’ll learn all the best practices for creating stunning visualizations.

Lastly, you will dive into scales and one of the more fun parts: adding animation and interactivity.

By the time you finish this course, you will have a powerful new library to add to your resume, and you’ll be able to transform data into meaningful insights.

Master D3.js for Data Visualization

#chart{
  width: 800px;
  height: 800px;
  background-color: #f7f7f7;
  margin: 25px auto;
  position: relative
}

#tooltip {
  text-align: center;
  border: 1px solid #ccc;
  position: absolute;
  padding: 10px;
  background-color: #fff;
  display: none;
}

#tooltip .metric-date {
  text-decoration: underline;
}

.axis {
  font-size: 18px;
  shape-rendering: geometricPrecision;
}


<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>D3 Scatterplot</title>
  
</head>

<body>
  <div id="chart"></div>

  <script src="https://d3js.org/d3.v6.min.js"></script>
  
</body>

</html>

async function draw() {
  // Data
  const dataset = await d3.json('/udata/1kL2GBJw8VB/data-4-1.json')

  const xAccessor = (d) => d.currently.humidity
  const yAccessor = (d) => d.currently.apparentTemperature
  
  // Dimensions
  let dimensions = {
    width: 800,
    height: 800,
    margin: {
      top: 50,
      right: 50,
      bottom: 50,
      left: 50
    }
  }

  dimensions.ctrWidth = dimensions.width - dimensions.margin.left - dimensions.margin.right;
  dimensions.ctrHeight = dimensions.height - dimensions.margin.top - dimensions.margin.bottom;

  // Draw Image
  const svg = d3.select("#chart")
    .append("svg")
    .attr("width", dimensions.width)
    .attr("height", dimensions.height)

  const ctr = svg.append("g") // <g>
    .attr(
      "transform",
      `translate(${dimensions.margin.left}, ${dimensions.margin.top})`
    )

  // Scales
  const xScale = d3.scaleLinear()
    .domain(d3.extent(dataset, xAccessor))
    .rangeRound([0, dimensions.ctrWidth])
    .clamp(true)

  const yScale = d3.scaleLinear()
    .domain(d3.extent(dataset, yAccessor))
    .rangeRound([0, dimensions.ctrHeight])
    .nice()
    .clamp(true)

  // Draw circles
  ctr.selectAll('circle')
    .data(dataset)
    .join('circle')
    .attr("cx", d => xScale(xAccessor(d)))
    .attr("cy", d => yScale(yAccessor(d)))
    .attr("r", 5)
    .attr("fill", 'red')

  // Axes
  const xAxis = d3.axisBottom(xScale)

  const xAxisGroup = ctr.append("g")
    .call(xAxis)
    .style("transform", `translateY(${dimensions.ctrHeight}px)`)
    .classed('axis', true)

  xAxisGroup.append("text")
    .attr("x", dimensions.ctrWidth / 2)
    .attr("y", dimensions.margin.bottom - 10)
    .attr("fill", "black")
    .text("Humidity")
    .style("text-anchor", "middle")


  xAxisGroup.append("text")
    .attr("x", dimensions.ctrWidth / 2)
    .attr("y", dimensions.margin.bottom - 10)
    .attr("fill", "black")
    .text("Humidity")

  const yAxis = d3.axisLeft(yScale);

  const yAxisGroup = ctr.append("g")
    .call(yAxis)
    .classed("axis", true);

  yAxisGroup.append("text")
    .attr("x", -dimensions.ctrHeight / 2)
    .attr("y", -dimensions.margin.left + 15)
    .attr("fill", "black")
    .html("Temperature (&deg;F)")
    .style("transform", "rotate(270deg)")
    .style("text-anchor", "middle")
}

draw()

codemirror

We can use scales to flip an axis since SVG's coordinate system goes from top to bottom for the y-axis.

Overview

SVG Basics

D3 Fundamentals

Drawing a Scatter Plot

Scales

Animations & Interactivity

Even More Charts!

Conclusion

Flipping the Y-axis