block by jmuyskens 75673b5f7338a88b83c2dda0c976eaed

Single time series chart with real data

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Demonstration of transforming CSV data using D3

For NICAR Beginning D3, 2017

Charts forked from d3indepth‘s block: DOM Manipulation

forked from darlacameron‘s block: 2. Transforming data

forked from darlacameron‘s block: 3. Drawing shapes

forked from anonymous‘s block: Time series chart with real data

forked from jmuyskens‘s block: Multiple time series chart with real data

forked from jmuyskens‘s block: Single time series chart with real data

script.js

var parseTime = d3.timeParse('%a %b %d %H:%M:%S +0000 %Y');
var formatTime = d3.timeFormat('%Y-%m-%d');
var parseFormattedTime = d3.timeParse('%Y-%m-%d');

var lineChart = function(data){
  // set the dimensions and margins of the graph
  var margin = {top: 20, right: 20, bottom: 60, left: 50},
      width = 606 - margin.left - margin.right,
      height = 181 - margin.top - margin.bottom;
	
  data = data.map(function(d) {
    d.date = parseTime(d.created_at)
    return d;
  }).filter(function(d) {
    return d.date >= d3.timeParse("%Y")("2017")
  });
  
  // NEST
  var nestedData = d3.nest()
    .key(function(d) { return formatTime(d.date); })
    .sortKeys(d3.ascending)
    .rollup(function(values) { return values.length; })
    .entries(data);
  
  var nestedDataMap = d3.nest()
    .key(function(d) { return formatTime(d.date); })
    .sortKeys(d3.ascending)
    .rollup(function(values) { return values.length; })
    .map(data);
  
  console.log(nestedDataMap, nestedDataMap['$2017-03-01']);
  
  
  var dateRange = [];
  
  var date = new Date(Date.UTC(2017, 0, 2));
	var endDate = new Date(Date.UTC(2017, 2, 2));
  while (date <= endDate) {
    dateRange.push(formatTime(date));
    date = new Date(date.setDate(date.getDate() + 1));
  }
  
  console.log(dateRange);
  
  /*nestedData = dateRange.map(function(d) {
    if (nestedDataMap.hasOwnProperty("$" + d)) {
      return {key: d, value: nestedDataMap["$" + d] };
    } else {
      return {key: d, value: 0}
    }
  });*/

  
  console.log(nestedData.length);
  

  // set the ranges
  var xScale = d3.scaleTime().range([0, width]);
  var yScale = d3.scaleLinear().range([height, 0]);

  // define the line
  var line = d3.line()
   .x(function(d) { return xScale(parseFormattedTime(d.key)); })
   .y(function(d) { return yScale(d.value); });

  //add a new svg to hold the chart
  var svg = d3.select("body").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 + ")");

  // Scale the range of the data
  xScale.domain(d3.extent(data, function(d) { return d.date; }));
  yScale.domain(d3.extent(nestedData, (d) => d.value));
  
  // Add the X Axis
  svg.append("g")
    .attr("transform", "translate(0," + height + ")")
    .call(d3.axisBottom(xScale));

  // Add the Y Axis
  svg.append("g")
    .call(d3.axisLeft(yScale));
  
  //console.log(line(nestedData))
  
  // Add the line path
  svg.selectAll("path.tweetline")
    .data([nestedData])
  	.enter().append('path')
    .attr("class", "tweetline")
    .attr("d", line);
};

index.html

<!DOCTYPE html>
<meta charset="utf-8">
<head>
	<title>Transforming data</title>
</head>

<style>
	body {
		font-family: "Helvetica Neue", Helvetica, sans-serif;
		font-size: 14px;
	}
	path {
    fill: none;
    stroke: #aaa;
  }
  .tweetline {
    stroke-width:2px;
  }
</style>

<body>
  
	<script src="//d3js.org/d3.v4.min.js"></script>
  
	<script src="script.js"></script>
  
  <script>
    d3.csv("realdonaldtrumpsinceelection.csv", function(error, data) {
      if (error) throw error;
      lineChart(data);
    });
  </script>
</body>
</html>