[dygraphs.git] / docs / index.html

<html>
  <head>
    <title>dygraphs JavaScript Library</title>
    <!--[if IE]>
    <script type="text/javascript" src="excanvas.js"></script>
    <![endif]-->
    <script type="text/javascript" src="dygraph-combined.js"></script>
    <style type="text/css">
      .thinborder {
        border-width: 1px;
        border-spacing: 0px;
        border-style: solid;
        border-color: black;
        border-collapse: collapse;
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      }
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  </head>
<body>
  <center>
    <p><span style="font-size:28pt;">dygraphs JavaScript Library</span><br/>
    <a href="http://code.google.com/p/dygraphs/">code.google.com/p/dygraphs</a></p>
  </center>

<p>The dygraphs JavaScript library produces produces interactive, zoomable charts of time series.</p>

<h3>Features</h3>
<ul>
  <li>Plots time series without using an external server or Flash</li>
  <li>Supports multiple data series</li>
  <li>Supports error bands around data series</li>
  <li>Displays values on mouseover</li>
  <li>Interactive zoom</li>
  <li>Adjustable averaging period</li>
  <li>Customizable click-through actions</li>
  <li>Compatible with the Google Visualization API</li>
</ul>

<h3>Caveats</h3>
<ul>
  <li>Requires Firefox 1.5+ or Safari/WebKit 1.3+.</li>
  <li>Internet Explorer is poorly supported.</li>
</ul>

<h2>Demo</h2>
<font size=-1>(Mouse over to highlight individual values. Click and drag to zoom. Double-click to zoom out.)</font><br/>
<table><tr><td>
<div id="demodiv" style="width:480px; height:320px;"></div>
</td><td valign=top>
<div id="status" style="width:200px; font-size:0.8em; padding-top:5px;"></div>
</td>
</tr></table>
<script type="text/javascript">
  g = new DateGraph(
          document.getElementById("demodiv"),
          function() {
            var zp = function(x) { if (x < 10) return "0"+x; else return x; };
            var r = "date,parabola,line,another line,sine wave\n";
            for (var i=1; i<=31; i++) {
            r += "200610" + zp(i);
            r += "," + 10*(i*(31-i));
            r += "," + 10*(8*i);
            r += "," + 10*(250 - 8*i);
            r += "," + 10*(125 + 125 * Math.sin(0.3*i));
            r += "\n";
            }
            return r;
          },
          null,
          {
            rollPeriod: 1,
            labelsDiv: document.getElementById('status'),
            labelsSeparateLines: true,
            labelsKMB: true,
            colors: ["hsl(180,60,50)",
                     "rgb(255,100,100)",
                     "#00DD55",
                     "rgba(50,50,200,0.4)"],
            padding: {left: 40, right: 30, top: 15, bottom: 15},
            strokeWidth: 3.0
          }
      );
</script>

<h2>Usage</h2>

<p>The dygraphs library depends on two other JS libraries: <a href="http://www.mochikit.com/">MochiKit</a> and <a href="http://www.liquidx.net/plotkit/">PlotKit</a>. Rather than tracking down copies of these libraries, I recommend using a packed version of dygraphs that combines all three libraries into a single JS file. Either grab this file from dygraph project's <a href="http://code.google.com/p/dygraphs/downloads/list">downloads</a> page or create it yourself by <a href="http://code.google.com/p/dygraphs/source/checkout">checking out</a> a copy of the code and running:

<pre>./generate-combined.sh</pre>

<p>The combined JS file is now in <code>dygraph-combined.js</code>. Here's a basic example to get things started:</p>

<table>
  <tr><th>HTML</th>
      <td rowspan=2><img src=arrow.gif /></td>
      <th>Output</th></tr>
<tr>
<td valign=top><pre>
&lt;html&gt;
&lt;head&gt;
&lt;script type="text/javascript" src="combined.js"&gt;&lt;/script&gt;
&lt;/head&gt;
&lt;body&gt;
&lt;div id="graphdiv"&gt;&lt;/div&gt;
&lt;script type="text/javascript"&gt;
  g = new Dygraph(
        document.getElementById("graphdiv"),  // containing div
        "Date,Temperature\n" +                // CSV or path to a CSV file.
        "20080507,75\n" +
        "20080508,70\n" +
        "20080509,80\n",
      );
&lt;/script&gt;
&lt;/body&gt;
&lt;/html&gt;
</pre>
</td><td valign=top>
  <div id="graphdiv"></div>
  <script type="text/javascript">
    g = new Dygraph(
        document.getElementById("graphdiv"),  // containing div
        "Date,Temperature\n" +                // CSV or path to a CSV file.
        "20080507,75\n" +
        "20080508,70\n" +
        "20080509,80\n"
      );
  </script>
</td></tr></table>

<p>In order to keep this example self-contained, the second parameter is a function that returns CSV data. These lines <i>must</i> begin with a date in the form <i>YYYYMMDD</i>. In most applications, it makes more sense to include a CSV file instead. If the second parameter to the constructor is a string, it will be interpreted as the path to a CSV file. The Dygraph will perform an XMLHttpRequest to retrieve this file and display the data when it becomes available. Make sure your CSV file is readable and serving from a place that understands XMLHttpRequest's! In particular, you cannot specify a CSV file using <code>"file:///"</code>. Here's an example: (data from <a href="http://www.wunderground.com/history/airport/KNUQ/2007/1/1/CustomHistory.html?dayend=31&monthend=12&yearend=2007&req_city=NA&req_state=NA&req_statename=NA">Weather Underground</a>)</p>

<table>
  <tr><th>HTML</th>
      <td rowspan=2><img src=arrow.gif /></td>
      <th>Output</th></tr>
<tr>
<td valign=top><pre>
&lt;html&gt;
&lt;head&gt;
&lt;script type="text/javascript" src="combined.js"&gt;&lt;/script&gt;
&lt;/head&gt;
&lt;body&gt;
&lt;div id="graphdiv" style="width:600px; height:300px;"&gt;&lt;/div&gt;
&lt;script type="text/javascript"&gt;
  g = new Dygraph(
        document.getElementById("graphdiv"),
        "temperatures.csv",  // path to CSV file
        {}                   // additional options
      );
&lt;/script&gt;
&lt;/body&gt;
&lt;/html&gt;
</pre>
</td><td valign=top>
  <div id="graphdiv2" style="width:600px; height:300px;"></div>
  <script type="text/javascript">
    g2 = new Dygraph(
          document.getElementById("graphdiv2"),
          "temperatures.csv", {}
        );
  </script>
</td></tr></table>

<p>Click <a href="temperatures.csv">here</a> to view the <code>temperatures.csv</code> file. There are a few things to note here:</p>

<ul>
  <li>The Dygraph sent off an XHR to get the temperatures.csv file.</li>
  <li>The labels were taken from the first line of <code>temperatures.csv</code>, which is <code>Date,High,Low</code>.</li>
  <li>The Dygraph automatically chose two different, easily-distinguishable colors for the two data series.</li>
  <li>The labels on the x-axis have switched from days to months. If you zoom in, they'll switch to weeks and then days.</li>
  <li>Some heuristics are used to determine a good vertical range for the data. The idea is to make all the data visible and have human-friendly values on the axis (i.e. 200 instead of 193.4). Generally this works well.</li>
  <li>The data is very spiky. A moving average would be easier to interpret.</li>
</ul>

<p>This problem can be fixed by specifying the appropriate options in the "additional options" parameter to the Dygraph constructor. To set the number of days for a moving average, use the <b>rollPeriod</b> option. Here's how it's done:</p>

<table>
  <tr><th>HTML</th>
      <td rowspan=2><img src=arrow.gif /></td>
      <th>Output</th></tr>
<tr>
<td valign=top><pre>
&lt;html&gt;
&lt;head&gt;
&lt;script type="text/javascript" src="combined.js"&gt;&lt;/script&gt;
&lt;/head&gt;
&lt;body&gt;
&lt;div id="graphdiv" style="width:600px; height:300px;"&gt;&lt;/div&gt;
&lt;script type="text/javascript"&gt;
  g = new Dygraph(
        document.getElementById("graphdiv"),
        "temperatures.csv",
        { rollPeriod: 7,
          showRoller: true,
        }
      );
&lt;/script&gt;
&lt;/body&gt;
&lt;/html&gt;
</pre>
</td><td valign=top>
  <div id="graphdiv3" style="width:600px; height:300px;"></div>
  <script type="text/javascript">
    g3 = new Dygraph(
          document.getElementById("graphdiv3"),
          "temperatures.csv",
          { rollPeriod: 7,
            showRoller: true,
          }
        );
  </script>
</td></tr></table>

<p>A rolling average can be set using the text box in the lower left-hand corner of the graph (the showRoller attribute is what makes this appear).</p>

<h2>Error Bars</h2>
<p>Another significant feature of the dygraphs library is the ability to display error bars around data series. One standard deviation must be specified for each data point. A +/-<i>n</i> sigma band will be drawn around the data series at that point. If a moving average is being displayed, dygraphs will compute the standard deviation of the average at each point. (i.e. <i>&sigma;</i> = sqrt((<i>&sigma;_1</i>^2 + <i>&sigma;_2</i>^2 + ... + <i>&sigma;_n</i>^2)/<i>n</i>))</p>

<p>Here's a demonstration. There are two data series. One is <code>N(100,10)</code> with a standard deviation of 10 specified at each point. The other is <code>N(80,20)</code> with a standard deviation of 20 specified at each point. The CSV file was generated using Octave and can be viewed <a href="twonormals.csv">here</a>.</p>

<table>
  <tr><th>HTML</th>
      <td rowspan=2><img src=arrow.gif /></td>
      <th>Output</th></tr>
<tr>
<td valign=top><pre>
&lt;html&gt;
&lt;head&gt;
&lt;script type="text/javascript"
  src="combined.js"&gt;&lt;/script&gt;
&lt;/head&gt;
&lt;body&gt;
&lt;div id="graphdiv" 
 style="width:800px; height:400px;"
 &gt;&lt;/div&gt;
&lt;script type="text/javascript"&gt;
$ = document.getElementById;
g = new Dygraph(
  $("graphdiv"),
  "twonormals.csv",
  { rollPeriod: 7,
    showRoller: true,
    errorBars: true,
    valueRange: [50,125]
  }
);
&lt;/script&gt;
&lt;/body&gt;
&lt;/html&gt;
</pre>
</td><td valign=top>
  <div id="graphdiv4" style="width:800px; height:400px;"></div>
  <script type="text/javascript">
$ = document.getElementById;
new Dygraph(
  document.getElementById("graphdiv4"),
  "twonormals.csv",
  { rollPeriod: 14,
    showRoller: true,
    errorBars: true,
    valueRange: [50, 125]
  }
);
  </script>
</td></tr></table>

<p>Things to note here:</p>
<ul>
  <li>The <b>errorBars</b> option affects both the interpretation of the CSV file and the display of the graph. When <b>errorBars</b> is set to true, each line is interpreted as <i>YYYYMMDD</i>,<i>A</i>,<i>sigma_A</i>,<i>B</i>,<i>sigma_B</i>,...</li>
  <li>The first line of the CSV file doesn't mention the error columns. In this case, it's just "Date,Series1,Series2".</li>
  <li>The averaging visibly affects the error bars. This is most clear if you crank up the rolling period to something like 100 days. For the earliest dates, there won't be 100 data points to average so the signal will be noisier. The error bars get smaller like sqrt(N) going forward in time until there's a full 100 points to average.</li>
  <li>The error bars are partially transparent. This can be seen when they overlap one another.</li>
</ul>

<h2>One last demo</h2>

<p>This chart shows monthly closes of the Dow Jones Industrial Average, both in nominal and real (i.e. adjusted for inflation) dollars. The shaded areas show its monthly high and low. CPI values with a base from 1982-84 are used to adjust for inflation.</p>

<div id=dow_chart style="width:1000px; height:400px;"></div>
<script type="text/javascript">
  // From http://www.econstats.com/eqty/eq_d_mi_3.csv
  dow = new Dygraph(
    document.getElementById('dow_chart'),
    "dow.txt",
    {
      showRoller: true,
      customBars: true,
      labelsKMB: true,
      padding: {left:30, right:30, top:5, bottom:5}
    });
</script>
<!--

Here is a script to regenerate the Dow Jones plot:

# Get unadjusted DJIA data in a nice format:
curl -O http://www.econstats.com/eqty/eq_d_mi_3.csv
sed '1,17d' eq_d_mi_3.csv | cut -d, -f1,6 | perl -pe 's/(\d{4}-\d\d)-\d\d/$1/g' | perl -pe 's/, */\t/' | grep -v 'na' | perl -ne 'chomp; ($m,$v) = split/\t/; $close{$m} = $v; if ($low{$m} == 0 || $v < $low{$m}) { $low{$m}=$v } if ($v > $high{$m}) { $high{$m} = $v } END { for $x(sort keys %close) { print "$x\t$low{$x}\t$close{$x}\t$high{$x}\n" } } ' > monthly-djia.tsv

# Fetch and format the CPI data:
curl 'http://data.bls.gov/PDQ/servlet/SurveyOutputServlet?series_id=CUUR0000SA0&years_option=all_years&periods_option=all_periods&output_type=column&output_format=text&delimiter=comma' > cpi-u.txt
sed '1,/Series Id,Year,/d' cpi-u.txt | sed '/^$/,$d' | cut -d, -f2,3,4 | perl -ne 'print if /,M(0[0-9]|1[012]),/' | perl -pe 's/(\d{4}),M(\d{2}),/$1-$2\t/g' > cpi-u.tsv

# Merge:
join -t'       ' cpi-u.tsv monthly-djia.tsv > annotated-djia.tsv
perl -ne 'BEGIN{print "Month,Nominal,Real\n"} chomp; ($m,$cpi,$low,$close,$high) = split /\t/; $cpi /= 100.0; print "$m-15,$low;$close;$high,",($low/$cpi),";",($close/$cpi),";",($high/$cpi),"\n"' annotated-djia.tsv > dow.txt

-->


<h2>Other Options</h2>
<p>These are the options that can be passed in through the optional third parameter of the Dygraph constructor.</p>

<table class=thinborder width=1000>
  <tr><th>Name</th><th>Sample Value</th><th>Description</th></tr>
  <tr>
    <td><b>rollPeriod</b></td>
    <td><code>7</code></td>
    <td>Number of days over which to average data. Discussed extensively above.</td>
  </tr><tr>
    <td><b>showRoller</b></td>
    <td><code>true</code></td>
    <td>Should the rolling average period text box be shown? Default is false.</td>
  </tr><tr>
    <td><b>colors</b></td>
    <td><code>['red',&nbsp;'#00FF00']</code></td>
    <td>List of colors for the data series. These can be of the form "#AABBCC"
      or "rgb(255,100,200)" or "yellow", etc. If not specified, equally-spaced
      points around a color wheel are used.</td>
  </tr><tr>
    <td><b>colorSaturation</b></td>
    <td><code>1.0</code></td>
    <td>If <b>colors</b> is not specified, saturation of the
      automatically-generated data series colors. (0.0-1.0, default:
      1.0)</td>
  </tr><tr>
    <td><b>colorValue</b></td>
    <td><code>0.5</code></td>
    <td>If colors is not specified, value of the data series colors, as in
      hue/saturation/value. (0.0-1.0, default 0.5)</td>
  </tr><tr>
    <td><b>clickCallback</b></td>
    <td><code>function(e,date){ alert(date); }</code></td>
    <td>A function to call when a data point is clicked. The function should take
      two arguments, the event object for the click and the date that was
      clicked. (default null)</td>
  </tr><tr>
    <td><b>errorBars</b></td>
    <td><code>false</code></td>
    <td>Does the data contain standard deviations? Setting this to true alters
      the input format (see above). (default false)</td>
  </tr><tr>
    <td><b>strokeWidth</b></td>
    <td><code>2.0</code></td>
    <td>Width of the data lines. This can be used to increase the contrast or
      some graphs. (default 1.0)</td>
  </tr><tr>
    <td><b>dateWindow</b></td>
    <td><code>[(new&nbsp;Date('2006-01-01')).valueOf(),<br/>
        (new&nbsp;Date()).valueOf()]</code></td>
    <td>Initially zoom in on a section of the graph. Is of the form [earliest,
      latest], where earliest/latest are millis since epoch.  By default, the
      full range of the input is shown.</td>
  </tr><tr>
    <td><b>valueRange</b></td>
    <td><code>[10, 110]</code></td>
    <td>Explicitly set the vertical range of the graph to [low, high]. By
      default, some clever heuristics are used (see above).</td>
  </tr><tr>
    <td><b>minTickSize</b></td>
    <td><code>1</code</td>
    <td>The difference between ticks on the y-axis can be greater than or equal
      to this, but no less. If you set it to 1, for instance, you'll never get
      nonintegral gaps between ticks.</td>
  </tr><tr>
    <td><b>labelsSeparateLines</b></td>
    <td><code>true</code></td>
    <td>Put &lt;br/&gt; between lines in the label string. Often used in
      conjunction with <b>labelsDiv</b>. (default false)</td>
  </tr><tr>
    <td><b>labelsDiv</b></td>
    <td><code>document.getElementById('foo')</code></td>
    <td>Show data labels in an external div, rather than on the graph. (default
      null)</td>
  </tr><tr>
    <td><b>labelsKMB</b></td>
    <td><code>true</code></td>
    <td>Show K/M/B for thousands/millions/billions on y-axis (default
      false).</td>
  </tr>
  <tr>
    <td><b>padding</b></td>
    <td><code>{left:&nbsp;40, right:&nbsp;30,<br/>top:&nbsp;5,
        bottom:&nbsp;15}</code></td>
    <td>Adds extra pixels of padding around the graph. Sometimes a dygraph
      gets clipped by surrounding text (see the Demo at the top of this page).
      Setting this property appropriately will fix this problem.</td>
  </tr>
</table>

<p>Any options you specify also get passed on to PlotKit's <a href="http://media.liquidx.net/js/plotkit-doc/PlotKit.Renderer.html">Renderer</a> class. dygraphs will override some of these (e.g. strokeColor), but others may be useful. The <code>padding</code> property is an example of this.</p>

<h2>Common Gotchas</h2>
<p>Here are a few problems that I've frequently run into while using the
dygraphs library.</p>

<ul>
  <li>Make sure your CSV files are readable! If your graph isn't showing up,
  the XMLHttpRequest for the CSV file may be failing. You can determine whether
  this is the case using tools like <a
    href="http://www.getfirebug.com/">Firebug</a>.</li>

  <li>Make sure your CSV files are in the correct format. They must be of the
  form <code>YYYYMMDD,series1,series2,...</code>. And if you set the
  <code>errorBars</code> property, make sure you alternate data series and
  standard deviations.</li>

  <li>dygraphs are not happy when placed inside a <code>&lt;center&gt;</code>
  tag. This applies to the CSS <code>text-align</code> property as well. If you
  want to center a Dygraph, put it inside a table with "align=center"
  set.</li>

  <li>Don't set the <code>dateWindow</code> property to a date. It expects
  milliseconds since epoch, which can be obtained from a JavaScript Date
  object's valueOf method.</li>
</ul>

<p><font size=-1>Created May 9, 2008 by <a href=mailto:danvdk@gmail.com>Dan Vanderkam</a></font></p>

</body>
</html>
Commit	Line	Data
078d1d29 DV	1	<html>
	2	<head>
	3	<title>dygraphs JavaScript Library</title>
	4	<!--[if IE]>
	5	<script type="text/javascript" src="excanvas.js"></script>
	6	<![endif]-->
9f006dbf	7	<script type="text/javascript" src="dygraph-combined.js"></script>
078d1d29 DV	8	<style type="text/css">
	9	.thinborder {
	10	border-width: 1px;
	11	border-spacing: 0px;
	12	border-style: solid;
	13	border-color: black;
	14	border-collapse: collapse;
	15	}
	16	.thinborder td, .thinborder th {
	17	border-width: 1px;
	18	padding: 5px;
	19	border-style: solid;
	20	border-color: black;
	21	}
	22	</style>
	23	</head>
	24	<body>
	25	<center>
52e5492a DV	26	<p><span style="font-size:28pt;">dygraphs JavaScript Library</span><br/>
52e5492a DV	27	<a href="http://code.google.com/p/dygraphs/">code.google.com/p/dygraphs</a></p>
078d1d29 DV	28	</center>
078d1d29 DV	29
285a6bda	30	<p>The dygraphs JavaScript library produces produces interactive, zoomable charts of time series.</p>
078d1d29 DV	31
	32	<h3>Features</h3>
	33	<ul>
	34	<li>Plots time series without using an external server or Flash</li>
	35	<li>Supports multiple data series</li>
	36	<li>Supports error bands around data series</li>
	37	<li>Displays values on mouseover</li>
	38	<li>Interactive zoom</li>
	39	<li>Adjustable averaging period</li>
	40	<li>Customizable click-through actions</li>
285a6bda	41	<li>Compatible with the Google Visualization API</li>
078d1d29 DV	42	</ul>
	43
	44	<h3>Caveats</h3>
	45	<ul>
	46	<li>Requires Firefox 1.5+ or Safari/WebKit 1.3+.</li>
04aa50fd	47	<li>Internet Explorer is poorly supported.</li>
078d1d29 DV	48	</ul>
	49
	50	<h2>Demo</h2>
	51	<font size=-1>(Mouse over to highlight individual values. Click and drag to zoom. Double-click to zoom out.)</font><br/>
	52	<table><tr><td>
	53	<div id="demodiv" style="width:480px; height:320px;"></div>
	54	</td><td valign=top>
52e5492a	55	<div id="status" style="width:200px; font-size:0.8em; padding-top:5px;"></div>
078d1d29	56	</td>
6153f697	57	</tr></table>
078d1d29 DV	58	<script type="text/javascript">
	59	g = new DateGraph(
	60	document.getElementById("demodiv"),
	61	function() {
ca433857	62	var zp = function(x) { if (x < 10) return "0"+x; else return x; };
078d1d29 DV	63	var r = "date,parabola,line,another line,sine wave\n";
078d1d29 DV	64	for (var i=1; i<=31; i++) {
ca433857	65	r += "200610" + zp(i);
078d1d29 DV	66	r += "," + 10(i(31-i));
	67	r += "," + 10(8i);
	68	r += "," + 10(250 - 8i);
	69	r += "," + 10(125 + 125 Math.sin(0.3*i));
	70	r += "\n";
	71	}
	72	return r;
	73	},
	74	null,
	75	{
	76	rollPeriod: 1,
	77	labelsDiv: document.getElementById('status'),
	78	labelsSeparateLines: true,
	79	labelsKMB: true,
	80	colors: ["hsl(180,60,50)",
	81	"rgb(255,100,100)",
	82	"#00DD55",
	83	"rgba(50,50,200,0.4)"],
2a6bfbd4 DV	84	padding: {left: 40, right: 30, top: 15, bottom: 15},
2a6bfbd4 DV	85	strokeWidth: 3.0
078d1d29 DV	86	}
	87	);
	88	</script>
	89
	90	<h2>Usage</h2>
	91
285a6bda	92	<p>The dygraphs library depends on two other JS libraries: <a href="http://www.mochikit.com/">MochiKit</a> and <a href="http://www.liquidx.net/plotkit/">PlotKit</a>. Rather than tracking down copies of these libraries, I recommend using a packed version of dygraphs that combines all three libraries into a single JS file. Either grab this file from dygraph project's <a href="http://code.google.com/p/dygraphs/downloads/list">downloads</a> page or create it yourself by <a href="http://code.google.com/p/dygraphs/source/checkout">checking out</a> a copy of the code and running:
078d1d29	93
9f006dbf	94	<pre>./generate-combined.sh</pre>
078d1d29	95
9f006dbf	96	<p>The combined JS file is now in <code>dygraph-combined.js</code>. Here's a basic example to get things started:</p>
078d1d29 DV	97
	98	<table>
	99	<tr><th>HTML</th>
	100	<td rowspan=2><img src=arrow.gif /></td>
	101	<th>Output</th></tr>
	102	<tr>
	103	<td valign=top><pre>
	104	<html>
	105	<head>
	106	<script type="text/javascript" src="combined.js"></script>
	107	</head>
	108	<body>
285a6bda	109	<div id="graphdiv"></div>
078d1d29	110	<script type="text/javascript">
285a6bda	111	g = new Dygraph(
078d1d29	112	document.getElementById("graphdiv"), // containing div
285a6bda DV	113	"Date,Temperature\n" + // CSV or path to a CSV file.
	114	"20080507,75\n" +
	115	"20080508,70\n" +
	116	"20080509,80\n",
078d1d29 DV	117	);
	118	</script>
	119	</body>
	120	</html>
	121	</pre>
	122	</td><td valign=top>
285a6bda	123	<div id="graphdiv"></div>
078d1d29	124	<script type="text/javascript">
285a6bda DV	125	g = new Dygraph(
	126	document.getElementById("graphdiv"), // containing div
	127	"Date,Temperature\n" + // CSV or path to a CSV file.
	128	"20080507,75\n" +
	129	"20080508,70\n" +
	130	"20080509,80\n"
	131	);
078d1d29 DV	132	</script>
	133	</td></tr></table>
	134
285a6bda	135	<p>In order to keep this example self-contained, the second parameter is a function that returns CSV data. These lines <i>must</i> begin with a date in the form <i>YYYYMMDD</i>. In most applications, it makes more sense to include a CSV file instead. If the second parameter to the constructor is a string, it will be interpreted as the path to a CSV file. The Dygraph will perform an XMLHttpRequest to retrieve this file and display the data when it becomes available. Make sure your CSV file is readable and serving from a place that understands XMLHttpRequest's! In particular, you cannot specify a CSV file using <code>"file:///"</code>. Here's an example: (data from <a href="http://www.wunderground.com/history/airport/KNUQ/2007/1/1/CustomHistory.html?dayend=31&monthend=12&yearend=2007&req_city=NA&req_state=NA&req_statename=NA">Weather Underground</a>)</p>
078d1d29 DV	136
	137	<table>
	138	<tr><th>HTML</th>
	139	<td rowspan=2><img src=arrow.gif /></td>
	140	<th>Output</th></tr>
	141	<tr>
	142	<td valign=top><pre>
	143	<html>
	144	<head>
	145	<script type="text/javascript" src="combined.js"></script>
	146	</head>
	147	<body>
	148	<div id="graphdiv" style="width:600px; height:300px;"></div>
	149	<script type="text/javascript">
285a6bda	150	g = new Dygraph(
078d1d29 DV	151	document.getElementById("graphdiv"),
078d1d29 DV	152	"temperatures.csv", // path to CSV file
285a6bda	153	{} // additional options
078d1d29 DV	154	);
	155	</script>
	156	</body>
	157	</html>
	158	</pre>
	159	</td><td valign=top>
	160	<div id="graphdiv2" style="width:600px; height:300px;"></div>
	161	<script type="text/javascript">
285a6bda	162	g2 = new Dygraph(
078d1d29	163	document.getElementById("graphdiv2"),
285a6bda	164	"temperatures.csv", {}
078d1d29 DV	165	);
	166	</script>
	167	</td></tr></table>
	168
	169	<p>Click <a href="temperatures.csv">here</a> to view the <code>temperatures.csv</code> file. There are a few things to note here:</p>
	170
	171	<ul>
285a6bda DV	172	<li>The Dygraph sent off an XHR to get the temperatures.csv file.</li>
	173	<li>The labels were taken from the first line of <code>temperatures.csv</code>, which is <code>Date,High,Low</code>.</li>
	174	<li>The Dygraph automatically chose two different, easily-distinguishable colors for the two data series.</li>
078d1d29	175	<li>The labels on the x-axis have switched from days to months. If you zoom in, they'll switch to weeks and then days.</li>
285a6bda	176	<li>Some heuristics are used to determine a good vertical range for the data. The idea is to make all the data visible and have human-friendly values on the axis (i.e. 200 instead of 193.4). Generally this works well.</li>
078d1d29 DV	177	<li>The data is very spiky. A moving average would be easier to interpret.</li>
	178	</ul>
	179
285a6bda	180	<p>This problem can be fixed by specifying the appropriate options in the "additional options" parameter to the Dygraph constructor. To set the number of days for a moving average, use the <b>rollPeriod</b> option. Here's how it's done:</p>
078d1d29 DV	181
	182	<table>
	183	<tr><th>HTML</th>
	184	<td rowspan=2><img src=arrow.gif /></td>
	185	<th>Output</th></tr>
	186	<tr>
	187	<td valign=top><pre>
	188	<html>
	189	<head>
	190	<script type="text/javascript" src="combined.js"></script>
	191	</head>
	192	<body>
	193	<div id="graphdiv" style="width:600px; height:300px;"></div>
	194	<script type="text/javascript">
285a6bda	195	g = new Dygraph(
078d1d29	196	document.getElementById("graphdiv"),
285a6bda	197	"temperatures.csv",
078d1d29	198	{ rollPeriod: 7,
738fc797	199	showRoller: true,
078d1d29 DV	200	}
	201	);
	202	</script>
	203	</body>
	204	</html>
	205	</pre>
	206	</td><td valign=top>
	207	<div id="graphdiv3" style="width:600px; height:300px;"></div>
	208	<script type="text/javascript">
285a6bda	209	g3 = new Dygraph(
078d1d29	210	document.getElementById("graphdiv3"),
285a6bda	211	"temperatures.csv",
078d1d29	212	{ rollPeriod: 7,
738fc797	213	showRoller: true,
078d1d29 DV	214	}
	215	);
	216	</script>
	217	</td></tr></table>
	218
738fc797	219	<p>A rolling average can be set using the text box in the lower left-hand corner of the graph (the showRoller attribute is what makes this appear).</p>
078d1d29 DV	220
078d1d29 DV	221	<h2>Error Bars</h2>
285a6bda	222	<p>Another significant feature of the dygraphs library is the ability to display error bars around data series. One standard deviation must be specified for each data point. A +/-<i>n</i> sigma band will be drawn around the data series at that point. If a moving average is being displayed, dygraphs will compute the standard deviation of the average at each point. (i.e. <i>σ</i> = sqrt((<i>σ_1</i>^2 + <i>σ_2</i>^2 + ... + <i>σ_n</i>^2)/<i>n</i>))</p>
078d1d29 DV	223
	224	<p>Here's a demonstration. There are two data series. One is <code>N(100,10)</code> with a standard deviation of 10 specified at each point. The other is <code>N(80,20)</code> with a standard deviation of 20 specified at each point. The CSV file was generated using Octave and can be viewed <a href="twonormals.csv">here</a>.</p>
	225
	226	<table>
	227	<tr><th>HTML</th>
	228	<td rowspan=2><img src=arrow.gif /></td>
	229	<th>Output</th></tr>
	230	<tr>
	231	<td valign=top><pre>
	232	<html>
	233	<head>
	234	<script type="text/javascript"
	235	src="combined.js"></script>
	236	</head>
	237	<body>
	238	<div id="graphdiv"
	239	style="width:800px; height:400px;"
	240	></div>
	241	<script type="text/javascript">
	242	$ = document.getElementById;
285a6bda	243	g = new Dygraph(
078d1d29 DV	244	$("graphdiv"),
078d1d29 DV	245	"twonormals.csv",
078d1d29	246	{ rollPeriod: 7,
738fc797	247	showRoller: true,
078d1d29 DV	248	errorBars: true,
	249	valueRange: [50,125]
	250	}
	251	);
	252	</script>
	253	</body>
	254	</html>
	255	</pre>
	256	</td><td valign=top>
	257	<div id="graphdiv4" style="width:800px; height:400px;"></div>
	258	<script type="text/javascript">
	259	$ = document.getElementById;
285a6bda	260	new Dygraph(
078d1d29 DV	261	document.getElementById("graphdiv4"),
078d1d29 DV	262	"twonormals.csv",
078d1d29	263	{ rollPeriod: 14,
738fc797	264	showRoller: true,
078d1d29 DV	265	errorBars: true,
	266	valueRange: [50, 125]
	267	}
	268	);
	269	</script>
	270	</td></tr></table>
	271
	272	<p>Things to note here:</p>
	273	<ul>
	274	<li>The <b>errorBars</b> option affects both the interpretation of the CSV file and the display of the graph. When <b>errorBars</b> is set to true, each line is interpreted as <i>YYYYMMDD</i>,<i>A</i>,<i>sigma_A</i>,<i>B</i>,<i>sigma_B</i>,...</li>
	275	<li>The first line of the CSV file doesn't mention the error columns. In this case, it's just "Date,Series1,Series2".</li>
	276	<li>The averaging visibly affects the error bars. This is most clear if you crank up the rolling period to something like 100 days. For the earliest dates, there won't be 100 data points to average so the signal will be noisier. The error bars get smaller like sqrt(N) going forward in time until there's a full 100 points to average.</li>
	277	<li>The error bars are partially transparent. This can be seen when they overlap one another.</li>
	278	</ul>
	279
353a0294 DV	280	<h2>One last demo</h2>
	281
	282	<p>This chart shows monthly closes of the Dow Jones Industrial Average, both in nominal and real (i.e. adjusted for inflation) dollars. The shaded areas show its monthly high and low. CPI values with a base from 1982-84 are used to adjust for inflation.</p>
	283
	284	<div id=dow_chart style="width:1000px; height:400px;"></div>
	285	<script type="text/javascript">
	286	// From http://www.econstats.com/eqty/eq_d_mi_3.csv
285a6bda	287	dow = new Dygraph(
353a0294 DV	288	document.getElementById('dow_chart'),
353a0294 DV	289	"dow.txt",
353a0294	290	{
738fc797	291	showRoller: true,
353a0294 DV	292	customBars: true,
	293	labelsKMB: true,
	294	padding: {left:30, right:30, top:5, bottom:5}
	295	});
	296	</script>
94a2e379 DV	297	<!--
	298
	299	Here is a script to regenerate the Dow Jones plot:
	300
	301	# Get unadjusted DJIA data in a nice format:
	302	curl -O http://www.econstats.com/eqty/eq_d_mi_3.csv
	303	sed '1,17d' eq_d_mi_3.csv \| cut -d, -f1,6 \| perl -pe 's/(\d{4}-\d\d)-\d\d/$1/g' \| perl -pe 's/, */\t/' \| grep -v 'na' \| perl -ne 'chomp; ($m,$v) = split/\t/; $close{$m} = $v; if ($low{$m} == 0 \|\| $v < $low{$m}) { $low{$m}=$v } if ($v > $high{$m}) { $high{$m} = $v } END { for $x(sort keys %close) { print "$x\t$low{$x}\t$close{$x}\t$high{$x}\n" } } ' > monthly-djia.tsv
	304
	305	# Fetch and format the CPI data:
	306	curl 'http://data.bls.gov/PDQ/servlet/SurveyOutputServlet?series_id=CUUR0000SA0&years_option=all_years&periods_option=all_periods&output_type=column&output_format=text&delimiter=comma' > cpi-u.txt
	307	sed '1,/Series Id,Year,/d' cpi-u.txt \| sed '/^$/,$d' \| cut -d, -f2,3,4 \| perl -ne 'print if /,M(0[0-9]\|1[012]),/' \| perl -pe 's/(\d{4}),M(\d{2}),/$1-$2\t/g' > cpi-u.tsv
	308
	309	# Merge:
	310	join -t' ' cpi-u.tsv monthly-djia.tsv > annotated-djia.tsv
	311	perl -ne 'BEGIN{print "Month,Nominal,Real\n"} chomp; ($m,$cpi,$low,$close,$high) = split /\t/; $cpi /= 100.0; print "$m-15,$low;$close;$high,",($low/$cpi),";",($close/$cpi),";",($high/$cpi),"\n"' annotated-djia.tsv > dow.txt
	312
	313	-->
353a0294 DV	314
353a0294 DV	315
078d1d29	316	<h2>Other Options</h2>
285a6bda	317	<p>These are the options that can be passed in through the optional third parameter of the Dygraph constructor.</p>
078d1d29 DV	318
	319	<table class=thinborder width=1000>
	320	<tr><th>Name</th><th>Sample Value</th><th>Description</th></tr>
	321	<tr>
	322	<td><b>rollPeriod</b></td>
	323	<td><code>7</code></td>
	324	<td>Number of days over which to average data. Discussed extensively above.</td>
	325	</tr><tr>
738fc797 DV	326	<td><b>showRoller</b></td>
	327	<td><code>true</code></td>
	328	<td>Should the rolling average period text box be shown? Default is false.</td>
	329	</tr><tr>
078d1d29 DV	330	<td><b>colors</b></td>
	331	<td><code>['red', '#00FF00']</code></td>
	332	<td>List of colors for the data series. These can be of the form "#AABBCC"
	333	or "rgb(255,100,200)" or "yellow", etc. If not specified, equally-spaced
	334	points around a color wheel are used.</td>
	335	</tr><tr>
	336	<td><b>colorSaturation</b></td>
	337	<td><code>1.0</code></td>
	338	<td>If <b>colors</b> is not specified, saturation of the
	339	automatically-generated data series colors. (0.0-1.0, default:
	340	1.0)</td>
	341	</tr><tr>
	342	<td><b>colorValue</b></td>
	343	<td><code>0.5</code></td>
	344	<td>If colors is not specified, value of the data series colors, as in
	345	hue/saturation/value. (0.0-1.0, default 0.5)</td>
	346	</tr><tr>
	347	<td><b>clickCallback</b></td>
	348	<td><code>function(e,date){ alert(date); }</code></td>
	349	<td>A function to call when a data point is clicked. The function should take
	350	two arguments, the event object for the click and the date that was
	351	clicked. (default null)</td>
	352	</tr><tr>
	353	<td><b>errorBars</b></td>
	354	<td><code>false</code></td>
	355	<td>Does the data contain standard deviations? Setting this to true alters
	356	the input format (see above). (default false)</td>
	357	</tr><tr>
	358	<td><b>strokeWidth</b></td>
	359	<td><code>2.0</code></td>
	360	<td>Width of the data lines. This can be used to increase the contrast or
	361	some graphs. (default 1.0)</td>
	362	</tr><tr>
	363	<td><b>dateWindow</b></td>
	364	<td><code>[(new Date('2006-01-01')).valueOf(),<br/>
	365	(new Date()).valueOf()]</code></td>
	366	<td>Initially zoom in on a section of the graph. Is of the form [earliest,
	367	latest], where earliest/latest are millis since epoch. By default, the
	368	full range of the input is shown.</td>
	369	</tr><tr>
	370	<td><b>valueRange</b></td>
	371	<td><code>[10, 110]</code></td>
	372	<td>Explicitly set the vertical range of the graph to [low, high]. By
	373	default, some clever heuristics are used (see above).</td>
	374	</tr><tr>
	375	<td><b>minTickSize</b></td>
	376	<td><code>1</code</td>
	377	<td>The difference between ticks on the y-axis can be greater than or equal
	378	to this, but no less. If you set it to 1, for instance, you'll never get
	379	nonintegral gaps between ticks.</td>
	380	</tr><tr>
	381	<td><b>labelsSeparateLines</b></td>
	382	<td><code>true</code></td>
	383	<td>Put <br/> between lines in the label string. Often used in
	384	conjunction with <b>labelsDiv</b>. (default false)</td>
	385	</tr><tr>
	386	<td><b>labelsDiv</b></td>
	387	<td><code>document.getElementById('foo')</code></td>
	388	<td>Show data labels in an external div, rather than on the graph. (default
	389	null)</td>
	390	</tr><tr>
	391	<td><b>labelsKMB</b></td>
	392	<td><code>true</code></td>
	393	<td>Show K/M/B for thousands/millions/billions on y-axis (default
394	false).</td>
395	</tr>
396	<tr>
397	<td><b>padding</b></td>
398	<td><code>{left: 40, right: 30,<br/>top: 5,
399	bottom: 15}</code></td>
400	<td>Adds extra pixels of padding around the graph. Sometimes a dygraph
401	gets clipped by surrounding text (see the Demo at the top of this page).
402	Setting this property appropriately will fix this problem.</td>
403	</tr>
404	</table>
405
285a6bda	406	<p>Any options you specify also get passed on to PlotKit's <a href="http://media.liquidx.net/js/plotkit-doc/PlotKit.Renderer.html">Renderer</a> class. dygraphs will override some of these (e.g. strokeColor), but others may be useful. The <code>padding</code> property is an example of this.</p>
078d1d29 DV	407
	408	<h2>Common Gotchas</h2>
	409	<p>Here are a few problems that I've frequently run into while using the
	410	dygraphs library.</p>
	411
	412	<ul>
	413	<li>Make sure your CSV files are readable! If your graph isn't showing up,
	414	the XMLHttpRequest for the CSV file may be failing. You can determine whether
	415	this is the case using tools like <a
	416	href="http://www.getfirebug.com/">Firebug</a>.</li>
	417
	418	<li>Make sure your CSV files are in the correct format. They must be of the
285a6bda DV	419	form <code>YYYYMMDD,series1,series2,...</code>. And if you set the
	420	<code>errorBars</code> property, make sure you alternate data series and
	421	standard deviations.</li>
078d1d29 DV	422
	423	<li>dygraphs are not happy when placed inside a <code><center></code>
	424	tag. This applies to the CSS <code>text-align</code> property as well. If you
285a6bda	425	want to center a Dygraph, put it inside a table with "align=center"
078d1d29 DV	426	set.</li>
078d1d29 DV	427
078d1d29 DV	428	<li>Don't set the <code>dateWindow</code> property to a date. It expects
	429	milliseconds since epoch, which can be obtained from a JavaScript Date
	430	object's valueOf method.</li>
	431	</ul>
	432
	433	<p><font size=-1>Created May 9, 2008 by <a href=mailto:danvdk@gmail.com>Dan Vanderkam</a></font></p>
	434
	435	</body>
	436	</html>