Stacked barplot with tooltip





This document describes how to build a stacked barplot with tooltip with d3.js. It follows the previous basic stacked barplot, and just extend it to show tooltip when a group is hovered. This example works with d3.js v4 and v6


Barplot section

Steps:

  • Follows the previous basic stacked barplot

  • Visit the tooltip section of the gallery to understand the general logic behind tooltip.

  • Here, the tricky part is to recover the subgroup name to show it in the tooltip. The trick is to use d3.select(this.parentNode).datum().key
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<!DOCTYPE html>
<meta charset="utf-8">

<!-- Load d3.js -->
<script src="https://d3js.org/d3.v4.js"></script>

<!-- Create a div where the graph will take place -->
<div id="my_dataviz"></div>

<!DOCTYPE html>
<meta charset="utf-8">
          
<!-- Load d3.js -->
<script src="https://d3js.org/d3.v6.js"></script>
          
<!-- Create a div where the graph will take place -->
<div id="my_dataviz"></div>
      
<script>

// set the dimensions and margins of the graph
var margin = {top: 10, right: 30, bottom: 20, left: 50},
    width = 460 - margin.left - margin.right,
    height = 400 - margin.top - margin.bottom;

// append the svg object to the body of the page
var svg = d3.select("#my_dataviz")
  .append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform",
          "translate(" + margin.left + "," + margin.top + ")");

// Parse the Data
d3.csv("https://raw.githubusercontent.com/holtzy/D3-graph-gallery/master/DATA/data_stacked.csv", function(data) {

  // List of subgroups = header of the csv files = soil condition here
  var subgroups = data.columns.slice(1)

  // List of groups = species here = value of the first column called group -> I show them on the X axis
  var groups = d3.map(data, function(d){return(d.group)}).keys()

  // Add X axis
  var x = d3.scaleBand()
      .domain(groups)
      .range([0, width])
      .padding([0.2])
  svg.append("g")
    .attr("transform", "translate(0," + height + ")")
    .call(d3.axisBottom(x).tickSizeOuter(0));

  // Add Y axis
  var y = d3.scaleLinear()
    .domain([0, 60])
    .range([ height, 0 ]);
  svg.append("g")
    .call(d3.axisLeft(y));

  // color palette = one color per subgroup
  var color = d3.scaleOrdinal()
    .domain(subgroups)
    .range(['#C7EFCF','#FE5F55','#EEF5DB'])

  //stack the data? --> stack per subgroup
  var stackedData = d3.stack()
    .keys(subgroups)
    (data)




  // ----------------
  // Create a tooltip
  // ----------------
  var tooltip = d3.select("#my_dataviz")
    .append("div")
    .style("opacity", 0)
    .attr("class", "tooltip")
    .style("background-color", "white")
    .style("border", "solid")
    .style("border-width", "1px")
    .style("border-radius", "5px")
    .style("padding", "10px")

  // Three function that change the tooltip when user hover / move / leave a cell
  var mouseover = function(d) {
    var subgroupName = d3.select(this.parentNode).datum().key;
    var subgroupValue = d.data[subgroupName];
    tooltip
        .html("subgroup: " + subgroupName + "<br>" + "Value: " + subgroupValue)
        .style("opacity", 1)
  }
  var mousemove = function(d) {
    tooltip
      .style("left", (d3.mouse(this)[0]+90) + "px") // It is important to put the +90: other wise the tooltip is exactly where the point is an it creates a weird effect
      .style("top", (d3.mouse(this)[1]) + "px")
  }
  var mouseleave = function(d) {
    tooltip
      .style("opacity", 0)
  }




  // Show the bars
  svg.append("g")
    .selectAll("g")
    // Enter in the stack data = loop key per key = group per group
    .data(stackedData)
    .enter().append("g")
      .attr("fill", function(d) { return color(d.key); })
      .selectAll("rect")
      // enter a second time = loop subgroup per subgroup to add all rectangles
      .data(function(d) { return d; })
      .enter().append("rect")
        .attr("x", function(d) { return x(d.data.group); })
        .attr("y", function(d) { return y(d[1]); })
        .attr("height", function(d) { return y(d[0]) - y(d[1]); })
        .attr("width",x.bandwidth())
        .attr("stroke", "grey")
      .on("mouseover", mouseover)
      .on("mousemove", mousemove)
      .on("mouseleave", mouseleave)

})

</script>
<script>

// set the dimensions and margins of the graph
const margin = {top: 10, right: 30, bottom: 20, left: 50},
    width = 460 - margin.left - margin.right,
    height = 400 - margin.top - margin.bottom;

// append the svg object to the body of the page
const svg = d3.select("#my_dataviz")
  .append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform",`translate(${margin.left},${margin.top})`);

// Parse the Data
d3.csv("https://raw.githubusercontent.com/holtzy/D3-graph-gallery/master/DATA/data_stacked.csv").then( function(data) {

  // List of subgroups = header of the csv files = soil condition here
  const subgroups = data.columns.slice(1)

  // List of groups = species here = value of the first column called group -> I show them on the X axis
  const groups = data.map(d => d.group)

  // Add X axis
  const x = d3.scaleBand()
      .domain(groups)
      .range([0, width])
      .padding([0.2])
  svg.append("g")
    .attr("transform", `translate(0, ${height})`)
    .call(d3.axisBottom(x).tickSizeOuter(0));

  // Add Y axis
  const y = d3.scaleLinear()
    .domain([0, 60])
    .range([ height, 0 ]);
  svg.append("g")
    .call(d3.axisLeft(y));

  // color palette = one color per subgroup
  const color = d3.scaleOrdinal()
    .domain(subgroups)
    .range(['#C7EFCF','#FE5F55','#EEF5DB'])

  //stack the data? --> stack per subgroup
  const stackedData = d3.stack()
    .keys(subgroups)
    (data)




  // ----------------
  // Create a tooltip
  // ----------------
  const tooltip = d3.select("#my_dataviz")
    .append("div")
    .style("opacity", 0)
    .attr("class", "tooltip")
    .style("background-color", "white")
    .style("border", "solid")
    .style("border-width", "1px")
    .style("border-radius", "5px")
    .style("padding", "10px")

  // Three function that change the tooltip when user hover / move / leave a cell
  const mouseover = function(event, d) {
    const subgroupName = d3.select(this.parentNode).datum().key;
    const subgroupValue = d.data[subgroupName];
    tooltip
        .html("subgroup: " + subgroupName + "<br>" + "Value: " + subgroupValue)
        .style("opacity", 1)
        
  }
  const mousemove = function(event, d) {
    tooltip.style("transform","translateY(-55%)")  
           .style("left",(event.x)/2+"px")
           .style("top",(event.y)/2-30+"px")
  }
  const mouseleave = function(event, d) {
    tooltip
      .style("opacity", 0)
  }

  // Show the bars
  svg.append("g")
    .selectAll("g")
    // Enter in the stack data = loop key per key = group per group
    .data(stackedData)
    .join("g")
      .attr("fill", d => color(d.key))
      .selectAll("rect")
      // enter a second time = loop subgroup per subgroup to add all rectangles
      .data(d => d)
      .join("rect")
        .attr("x", d =>  x(d.data.group))
        .attr("y", d => y(d[1]))
        .attr("height", d => y(d[0]) - y(d[1]))
        .attr("width",x.bandwidth())
        .attr("stroke", "grey")
      .on("mouseover", mouseover)
      .on("mousemove", mousemove)
      .on("mouseleave", mouseleave)

})

</script>

Related blocks →

  • Simple Box Plot Example in d3.js v4.0 - link

  • D3.js Boxplot with Axes and Labels - link