S18 - HW 3 - Bar Chart by Yash

CS 725/825 - Spring 2018 - Homework 3 - Bar Chart

The charts in the figure shows the frequency of usage of all the alphabets in English.

Details:

The mark for both Chart1 and Chart2 is a rectangular bar.
The channel was only the height of the bars. The alphabets are plotted on the X-axis and frequency on the Y-axis. The height varies depending on the frequenct of usage. The frequency is a quantitative attribute.
After making changes to Chart1, the new channel is color hue that varies for every alphabet. The attribute for the alphabets is a sequential attribute.
For Chart2, the new channel is color saturation which has been mapped to frequency. The saturation changes depending on the frequency from a lighter shade to a darker shade. The attribute for frequency is quantitative attribute.

Resources:

Following are the resources, that helped me in the process.

https://stackoverflow.com/
https://bl.ocks.org/pstuffa/3393ff2711a53975040077b7453781a9
https://github.com/d3/d3-scale-chromatic

<!DOCTYPE html>
<html>
<meta charset="utf-8">
<script src="https://d3js.org/d3.v4.min.js"></script>
<script src="https://d3js.org/d3-scale-chromatic.v1.min.js"></script> 
<script src="https://d3js.org/d3-color.v1.min.js"></script>
<script src="https://d3js.org/d3-hsv.v0.1.min.js"></script>
<style>   
  body {font-family: garamond;} 
  .axis {font: 14px garamond;}
  .label {font: 16px garamond;}
</style>

<body>
	<p>Frequency of usage of letters in English</p>
	<h2>Bar Chart 1</h2>
  <div><svg id="chart1" width="800" height="400"></svg></div>
	<h2>Bar Chart 2</h2>
  <div><svg id="chart2" width="800" height="400"></svg></div>

// creates new svg <g> space, sets new (0,0) at left, top margin
var g1 = svg1.append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");
var colorScale = d3.scaleOrdinal(d3.schemeCategory20);

d3.tsv("data.tsv", function(d) {
  d.frequency = +d.frequency;    // convert text to number
  return d;
}, function(error, data) {
  if (error) throw error;

// See https://www.dashingd3js.com/d3js-scales
  // maps domain of x values (letters) to range of positions on x-axis
  x1.domain(data.map(function(d) { return d.letter; }));  
  // maps domain of y values (frequencies 0, max freq) to range of positions on y-axis
  y1.domain([0, d3.max(data, function(d) { return d.frequency; })]); 
  // x-axis
  g1.append("g")
    .attr("class", "axis x-axis")
    .attr("transform", "translate(0," + height + ")") // move axis to bottom of chart
    .call(d3.axisBottom(x1));
  
  // y-axis
  g1.append("g")
    .attr("class", "axis y-axis")
    .call(d3.axisLeft(y1).ticks(10, "#")); // number of ticks and type

// y-axis label
  g1.append("text")
  	.attr("class", "label")
    .attr("x", 0-margin.left)       // set x position of label
    .attr("y", 0-margin.top/2)			// set y position of label
    .style("text-anchor", "start")  // left-justify
  	.text ("Frequency of Usage")
  
  // bars
  g1.selectAll(".bar")
    .data(data)
    .enter().append("rect")
      .attr("class", "bar")
      .attr("x", function(d) { console.log ("letter: " + d.letter + ", x: " + x1(d.letter)); return x1(d.letter); })
      .attr("y", function(d) { console.log ("freq: " + d.frequency + ", y: " + y1(d.frequency)); return y1(d.frequency); })
      .attr("width", x1.bandwidth()) // width of each band 
      .attr("height", function(d) { return height - y1(d.frequency); })
  		.style("fill", function(d, i) {return colorScale(i); })  // color of the bars
  ;
});
  
// chart 2  
var svg2 = d3.select("#chart2"),
    margin = {top: 20, right: 20, bottom: 30, left: 40},
    width = +svg2.attr("width") - margin.left - margin.right,
    height = +svg2.attr("height") - margin.top - margin.bottom;
var colour = d3.interpolateHsl('blue');
var x2 = d3.scaleBand().rangeRound([0, width]).padding(0.1),
    y2 = d3.scaleLinear().rangeRound([height, 0]);

var g2 = svg2.append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");
d3.tsv("data.tsv", function(d) {
  d.frequency = +d.frequency; 
  return d;
}, function(error, data) {
  if (error) throw error;

x2.domain(data.map(function(d) { return d.letter; }));
  y2.domain([0, d3.max(data, function(d) { return d.frequency; })]);

// x-axis
  g2.append("g")
    .attr("class", "axis axis--x")
    .attr("transform", "translate(0," + height + ")") 
    .call(d3.axisBottom(x2));

// y-axis
  g2.append("g")
    .attr("class", "axis axis--y")
    .call(d3.axisLeft(y2).ticks(10, "#"));

// y-axis label
  g2.append("text")
  	.attr("class", "label")
    .attr("x", 0-margin.left)
    .attr("y", 0-margin.top/2)
    .style("text-anchor", "begin")
  	.text ("Frequency of Usage")
  
  // bars
  g2.selectAll(".bar")
    .data(data)
    .enter().append("rect")
      .attr("class", "bar")
      .attr("x", function(d) { return x2(d.letter); })
      .attr("y", function(d) { return y2(d.frequency); })
      .attr("width", x2.bandwidth())
      .attr("height", function(d) { return height - y2(d.frequency); })
  		.style("fill", function (d,i) {return d3.interpolateGreys(d.frequency * 12); })/*{
             var returnColor;
             if (d.frequency < 0.00100) {returnColor = '#a2d1e1';}
             if (d.frequency > 0.00100 && d.frequency <= 0.00200) {returnColor ='#6bb7d0';}
             if (d.frequency > 0.00200 && d.frequency <= 0.03000) {returnColor ='#4ca8c6';}
             if (d.freqency > 0.03000 && d.frequency <= 0.04000) {returnColor = '#3594b4';}
             if (d.frequency > 0.04000 && d.frequency <= 0.06000) {returnColor ='#318ba9';}
             if (d.frequency > 0.06000 && d.frequency <= 0.08000) {returnColor ='#28758f';}
             if (d.frequency > 0.08000 && d.frequency <= 0.10000) {returnColor ='#194a5c';}
             if (d.frequency > 0.10000) {returnColor = '#154050';}
             return returnColor;
      })*/ 
  ;
});
</script>
</body>
</html>

https://d3js.org/d3.v4.min.js

https://d3js.org/d3-scale-chromatic.v1.min.js

https://d3js.org/d3-color.v1.min.js

https://d3js.org/d3-hsv.v0.1.min.js