Installing


// Use a script tag to include library
// d3 4.0 standard version 

// d3 4.0 minified version

// d3 3.x version


// Import D3 into an application
npm install d3 // installing command
import * as d3 from "d3"; // use in application

// include standalone D3 microlibraries

// or
import {scaleLinear} from "d3-scale";

4 steps to visualize your first chart

Construct a simple bar chart from TSV file

1. A HTML Template


<html>
<head>
	<meta charset="utf-8">
	<title>D3 Tutorial</title>
	<script src="https://d3js.org/d3.v4.min.js"></script>

	<style>
	.bar {
	  fill: steelblue;
	}
	.bar:hover {
	  fill: brown;
	}
	.axis--x path {
	  display: none;
	}
	</style>
</head>
<body>
	<div id="barchart"></div>
</body>
</html>

2. Initial svg and scale


// append a svg element and define margins
var svg = d3.select("#barchart")
	.append("svg")
	.attr("width", 960)
	.attr("height", 500),
    margin = {top: 20, right: 20, bottom: 30, left: 40},
    width = +svg.attr("width") - margin.left - margin.right,
    height = +svg.attr("height") - margin.top - margin.bottom;

// Constructs a new band scale (x) and a new continuous scale (y)
var x = d3.scaleBand().rangeRound([0, width]).padding(0.1),
    y = d3.scaleLinear().rangeRound([height, 0]);

// append g element
var transStr = "translate(" + margin.left + "," + margin.top + ")";
var g = svg.append("g")
    .attr("transform", transStr);

3. Load and format data


// d3 tsv Function
// Creates a request for the TSV file at the specified url 
// with the default mime type text/tab-separated-values
d3.tsv(url, row, callback);

d3.tsv("d3-tutorial-tsv-data.tsv", function(d) {
  d.frequency = +d.frequency;
  return d;
}, barchartCallback);

Requests (d3-request)

  • d3.csv - get a comma-separated values (CSV) file.
  • d3.html - get an HTML file.
  • d3.json - get a JSON file.
  • d3.text - get a plain text file.
  • d3.tsv - get a tab-separated values (TSV) file.
  • d3.xml - get an XML file.
    •

    4. Bind data and update element

    
function barchartCallback(error, data) {
  if (error) throw error;

  // Given a value from the domain
  // returns the corresponding value from the range.
  x.domain(data.map(function(d) { 
  	return d.letter; 
  }));
  y.domain([0, d3.max(data, function(d) { 
  	return d.frequency; 
  })]);

  // x axis
  g.append("g")
      .attr("class", "axis axis--x")
      .attr("transform", "translate(0," + height + ")")
      .call(d3.axisBottom(x));
  
  // y axis
  g.append("g")
      .attr("class", "axis axis--y")
      .call(d3.axisLeft(y).ticks(10, "%"))
    .append("text")
      .attr("transform", "rotate(-90)")
      .attr("y", 6)
      .attr("dy", "0.71em")
      .attr("text-anchor", "end")
      .text("Frequency");

  // bind data and define rect element generating rule
  g.selectAll(".bar")
    .data(data)
    .enter().append("rect")
      .attr("class", "bar")
      .attr("x", function(d) { return x(d.letter); })
      .attr("y", function(d) { return y(d.frequency); })
      .attr("width", x.bandwidth())
      .attr("height", function(d) { 
      	return height - y(d.frequency); 
      });
}

    5. Complete Codes

    
<html>
<head>
  <meta charset="utf-8">
  <title>D3 Tutorial</title>
  <script src="https://d3js.org/d3.v4.min.js"></script>

  <style>
  .bar {
    fill: steelblue;
  }
  .bar:hover {
    fill: brown;
  }
  .axis--x path {
    display: none;
  }
  </style>
</head>
<body>
  <div id="barchart"></div>

  <script>
    // append a svg element and define margins
    var svg = d3.select("#barchart")
      .append("svg")
      .attr("width", 960)
      .attr("height", 500),
        margin = {top: 20, right: 20, bottom: 30, left: 40},
        width = +svg.attr("width") - margin.left - margin.right,
        height = +svg.attr("height") - margin.top - margin.bottom;

    // Constructs a new band scale (x) and a new continuous scale (y)
    var x = d3.scaleBand().rangeRound([0, width]).padding(0.1),
        y = d3.scaleLinear().rangeRound([height, 0]);

    // append g element
    var transStr = "translate(" + margin.left + "," + margin.top + ")";
    var g = svg.append("g")
        .attr("transform", transStr);

    d3.tsv("./data/d3-tutorial-tsv-data.tsv", function(d) {
      d.frequency = +d.frequency;
      return d;
    }, barchartCallback);

    function barchartCallback(error, data) {
      if (error) throw error;

      // Given a value from the domain
      // returns the corresponding value from the range.
      x.domain(data.map(function(d) { 
        return d.letter; 
      }));
      y.domain([0, d3.max(data, function(d) { 
        return d.frequency; 
      })]);

      // x axis
      g.append("g")
          .attr("class", "axis axis--x")
          .attr("transform", "translate(0," + height + ")")
          .call(d3.axisBottom(x));
      
      // y axis
      g.append("g")
          .attr("class", "axis axis--y")
          .call(d3.axisLeft(y).ticks(10, "%"))
        .append("text")
          .attr("transform", "rotate(-90)")
          .attr("y", 6)
          .attr("dy", "0.71em")
          .attr("text-anchor", "end")
          .text("Frequency");

      // bind data and define rect element generating rule
      g.selectAll(".bar")
        .data(data)
        .enter().append("rect")
          .attr("class", "bar")
          .attr("x", function(d) { return x(d.letter); })
          .attr("y", function(d) { return y(d.frequency); })
          .attr("width", x.bandwidth())
          .attr("height", function(d) { 
            return height - y(d.frequency); 
          });
    }
  </script>
</body>
</html>

    More

    Be careful about the API's differences between 4.0 and 3.x

    Be careful about async loading in JavaScript

    Make good use of Google, Stack Overflow, etc.

    THE END

    @hijiangtao

    - d3js.org
    - VIS Course (2016 Fall) Wiki
    - Joe's Blog