title: Dynamically Update Multiple Charts in D3
body: <p>As stated by the title, I'm trying to dynamically update multiple line charts using D3. I have combined these two examples (<a href="http://bl.ocks.org/d3noob/6bd13f974d6516f3e491" rel="nofollow noreferrer">http://bl.ocks.org/d3noob/6bd13f974d6516f3e491</a> and <a href="http://bl.ocks.org/d3noob/5987480" rel="nofollow noreferrer">http://bl.ocks.org/d3noob/5987480</a>). Only the first chart is updating with the second remaining static.</p>
  
  <p>Here is the code:</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;meta charset="utf-8"&gt;
  &lt;style&gt; /* set the CSS */
  
  body { font: 12px Arial;}
  
  path { 
  stroke: steelblue;
  stroke-width: 2;
  fill: none;
  }
  
  .axis path,
  .axis line {
  fill: none;
  stroke: grey;
  stroke-width: 1;
  shape-rendering: crispEdges;
  }
  
  &lt;/style&gt;
  
  &lt;body&gt;
  
  &lt;!-- load the d3.js library --&gt; 
  &lt;script src="http://d3js.org/d3.v3.min.js"&gt;&lt;/script&gt;
  
  &lt;script&gt;
  
  // Set the dimensions of the canvas / graph
  var margin = {top: 30, right: 20, bottom: 30, left: 50},
  width = 400 - margin.left - margin.right,
  height = 220 - margin.top - margin.bottom;
  
  // Parse the date / time
  var parseDate = d3.time.format("%H:%M:%S").parse;
  
  // Set the ranges
  var x = d3.time.scale().range([0, width]);
  var y = d3.scale.linear().range([height, 0]);
  
  // Define the axes
  var xAxis = d3.svg.axis().scale(x)
  .orient("bottom").ticks(5);
  
  var yAxis = d3.svg.axis().scale(y)
  .orient("left").ticks(5);
  
  // Define the line
  var valueline = d3.svg.line()
  .x(function(d) { return x(d.date); })
  .y(function(d) { return y(d.temperature); });
  
  // Adds the svg canvas
  var chart1 = 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 + ")");
  
  // Get the data
  d3.csv("output.csv", function(error, data) {
  data.forEach(function(d) {
      d.date = parseDate(d.date);
      d.temperature = +d.temperature;
  });
  
  // Scale the range of the data
  x.domain(d3.extent(data, function(d) { return d.date; }));
  y.domain([0, d3.max(data, function(d) { return d.temperature; })]);
  
  // Add the valueline path.
  chart1.append("path")
      .attr("class", "line")
      .attr("d", valueline(data));
  
  // Add the X Axis
  chart1.append("g")
      .attr("class", "x axis")
      .attr("transform", "translate(0," + height + ")")
      .call(xAxis);
  
  // Add the Y Axis
  chart1.append("g")
      .attr("class", "y axis")
      .call(yAxis);
  
  });
  
  // Adds the svg canvas
  var chart2 = 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 + ")");
  
  // Get the data
  d3.csv("output2.csv", function(error, data) {
  data.forEach(function(d) {
      d.date = parseDate(d.date);
      d.humidity = +d.humidity;
  });
  
  // Scale the range of the data
  x.domain(d3.extent(data, function(d) { return d.date; }));
  y.domain([0, d3.max(data, function(d) { return d.humidity; })]);
  
  // Add the valueline path.
  chart2.append("path")
      .attr("class", "line")
      .attr("d", valueline(data));
  
  // Add the X Axis
  chart2.append("g")
      .attr("class", "x axis")
      .attr("transform", "translate(0," + height + ")")
      .call(xAxis);
  
  // Add the Y Axis
  chart2.append("g")
      .attr("class", "y axis")
      .call(yAxis);
  
  });
  
  //2 graph sample code ends here
  
  var TemperatureInterval = setInterval(function() {
              updateTemperatureData();
      }, 5000); 
  
  var HumidityInterval = setInterval(function() {
              updateHumidityData();
      }, 7000); 
  
  function updateTemperatureData() {
  
  // Get the data again
  d3.csv("output2.csv", function(error, data) {
      data.forEach(function(d) {
          d.date = parseDate(d.date);
          d.temperature = +d.temperature;
      });
  
      // Scale the range of the data again 
      x.domain(d3.extent(data, function(d) { return d.date; }));
      y.domain([0, d3.max(data, function(d) { return d.temperature; })]);
  
  // Select the section we want to apply our changes to
  var chart1 = d3.select("body").transition();
  
  // Make the changes
  
      chart1.select(".line")   // change the line
          .duration(750)
          .attr("d", valueline(data));
      chart1.select(".x.axis") // change the x axis
          .duration(750)
          .call(xAxis);
      chart1.select(".y.axis") // change the y axis
          .duration(750)
          .call(yAxis);
  
  });
  }
  
  function updateHumidityData() {
  
  // Get the data again
  d3.csv("output2.csv", function(error, data) {
      data.forEach(function(d) {
          d.date = parseDate(d.date);
          d.humidity = +d.humidity;
      });
  
      // Scale the range of the data again 
      x.domain(d3.extent(data, function(d) { return d.date; }));
      y.domain([0, d3.max(data, function(d) { return d.humidity; })]);
  
  // Select the section we want to apply our changes to
  var chart2 = d3.select("body").transition();
  
  // Make the changes
      chart2.select(".line")   // change the line
          .duration(750)
          .attr("d", valueline(data));
      chart2.select(".x.axis") // change the x axis
          .duration(750)
          .call(xAxis);
      chart2.select(".y.axis") // change the y axis
          .duration(750)
          .call(yAxis);
  
  });
  }
  
  &lt;/script&gt;
  &lt;/body&gt;
  </code></pre>
  
  <p>Thanks.</p>