docs/index.html

   1 <!DOCTYPE html>
   2 <html>
   3   <head>
   4     <meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7; IE=EmulateIE9">
   5     <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
   6
   7     <title>dygraphs JavaScript Visualization Library</title>
   8     <!--[if IE]>
   9       <script type="text/javascript" src="excanvas.js"></script>
  10     <![endif]-->
  11     <script type="text/javascript" src="dygraph-combined.js"></script>
  12     <link rel="stylesheet" href="style.css">
  13
  14     <!-- Google Analytics -->
  15     <script type="text/javascript">
  16       var _gaq = _gaq || [];
  17       _gaq.push(['_setAccount', 'UA-769809-2']);
  18       _gaq.push(['_trackPageview']);
  19       (function() {
  20         var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;
  21         ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
  22         var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);
  23       })();
  24     </script>
  25   </head>
  26   <body>
  27     <a href="http://github.com/danvk/dygraphs"><img style="position: absolute; top: 0; right: 0; border: 0;" src="https://a248.e.akamai.net/assets.github.com/img/71eeaab9d563c2b3c590319b398dd35683265e85/687474703a2f2f73332e616d617a6f6e6177732e636f6d2f6769746875622f726962626f6e732f666f726b6d655f72696768745f677261795f3664366436642e706e67" alt="Fork me on GitHub"></a>
  28
  29     <div id="nav">
  30       <h2>Documentation</h2>
  31       <ul>
  32         <li><a href="#demo">Demo</a></li>
  33         <li><a href="#usage">Usage</a></li>
  34         <li><a href="#ie">IE Compatibility</a></li>
  35         <li><a href="#gviz">GViz Data</a></li>
  36         <li><a href="#baseball">Baseball chart</a></li>
  37         <li><a href="#stock">Stock chart</a></li>
  38         <li><a href="#gwt">GWT Compatibility</a></li>
  39         <li><a href="#policy">Data Policy</a></li>
  40         <li><a href="options.html">Options Reference</a></li>
  41         <li><a href="jsdoc/symbols/Dygraph.html">JSDoc Reference</a></li>
  42         <li><a href="data.html">Data Formats</a></li>
  43         <li><a href="annotations.html">Annotations</a></li>
  44       </ul>
  45
  46       <h2>Project</h2>
  47       <ul>
  48         <li><a href="http://blog.dygraphs.com/">Blog</a></li>
  49         <li><a href="http://github.com/danvk/dygraphs">Source</a></li>
  50         <li><a href="http://code.google.com/p/dygraphs/issues/">Issues</a></li>
  51         <li><a href="http://code.google.com/p/dygraphs/issues/entry">Report Bug</a></li>
  52         <li><a href="changes.html">Contribute a change</a></li>
  53         <li><a href="mailto:dygraphs-users [at] googlegroups.com">Contact</a></li>
  54       </ul>
  55
  56       <h2>Demos/Usage</h2>
  57       <ul>
  58         <li><a href="#gallery">Usage Gallery</a></li>
  59         <hr/>
  60         <li><a href="tests/">(browse demos)</a></li>
  61         <li><a href="tests/demo.html">Basic Demo</a></li>
  62         <li><a href="tests/gviz.html">GViz Demo</a></li>
  63         <li><a href="tests/plotter.html">Equation Plotter</a></li>
  64         <li><a href="tests/perf.html">Performance Test</a></li>
  65         <li><a href="tests/annotation.html">Annotations</a></li>
  66         <li><a href="tests/annotation-gviz.html">Annotations (GViz)</a></li>
  67         <li><a href="tests/fillGraph.html">Filled Chart</a></li>
  68         <li><a href="tests/perf.html">Fractions</a></li>
  69         <li><a href="tests/visibility.html">Visibility</a></li>
  70         <li><a href="tests/label-div.html">Labels in a DIV</a></li>
  71         <li><a href="tests/numeric-axis.html">Numeric Axis</a></li>
  72         <li><a href="tests/draw-points.html">Dotted Points</a></li>
  73         <li><a href="tests/native-format.html">Native Format</a></li>
  74         <li><a href="tests/grid_dot.html">Crazy Styles</a></li>
  75         <li><a href="tests/spacing.html">Tick spacing</a></li>
  76         <li><a href="tests/callback.html">Callbacks</a></li>
  77         <li><a href="tests/crosshair.html">Crosshairs</a></li>
  78         <li><a href="tests/hourly.html">Hourly/Minutely data</a></li>
  79         <li><a href="tests/isolated-points.html">Isolated Points</a></li>
  80         <li><a href="tests/missing-data.html">Missing Data</a></li>
  81         <li><a href="tests/border.html">Bordered chart</a></li>
  82         <li><a href="tests/custom-bars.html">Custom Bars</a></li>
  83         <li><a href="tests/customLabel.html">Custom Label Styles</a></li>
  84         <li><a href="tests/dygraph.html">Minimal Example</a></li>
  85         <li><a href="tests/negative.html">Negative Numbers</a></li>
  86         <li><a href="tests/noise.html">Noisy Data</a></li>
  87         <li><a href="tests/two-series.html">Multiple Series</a></li>
  88         <li><a href="tests/highlighted-region.html">Custom Underlay / background</a></li>
  89         <li><a href="tests/zoom.html">Tests for zoom operations</a></li>
  90         <li><a href="tests/logscale.html">Log scale tests</a></li>
  91       </ul>
  92     </div>
  93
  94     <div id="content">
  95       <h1>dygraphs JavaScript Visualization Library</h1>
  96
  97       <p><a href="http://github.com/danvk/dygraphs">http://github.com/danvk/dygraphs</a></p>
  98       <p>See <a href="http://blog.dygraphs.com/">blog</a>, <a href="http://groups.google.com/group/dygraphs-users">mailing list</a>, <a href="http://github.com/danvk/dygraphs/downloads/">downloads</a>, <a href="tests/">demos</a> and <a href="http://code.google.com/p/dygraphs/issues/">open issues</a></p>
  99
 100       <p>dygraphs is an open source JavaScript library that produces produces interactive, zoomable charts of time series. It is designed to display dense data sets and enable users to explore and interpret them.</p>
 101
 102       <h3 id="demo">A demo is worth a thousand words:</h3>
 103
 104       <p style="font-size:0.8em">(Mouse over to highlight individual values. Click and drag to zoom. Double-click to zoom back out. Change the number and hit enter to adjust the averaging period.)</p>
 105
 106       <div id="demodiv" style="width:800px; height:320px;"></div>
 107       <script type="text/javascript">
 108         g = new Dygraph(
 109           document.getElementById("demodiv"),
 110           "ny-vs-sf.txt",
 111           {
 112             rollPeriod: 14,
 113             showRoller: true,
 114             customBars: true,
 115             title: 'Daily Temperatures in New York vs. San Francisco',
 116             ylabel: 'Temperature (F)',
 117             legend: 'always',
 118             labelsDivStyles: { 'textAlign': 'right' }
 119           }
 120         );
 121       </script>
 122
 123       <h4>Some things to notice:</h4>
 124       <ul>
 125         <li>There's less seasonal temperature variation in SF than in NY.</li>
 126         <li>The difference is about 15&deg; F for SF vs. 50&deg; F for NY.</li>
 127         <li>The daily data (set rolling period to 1) is quite noisy and hides this conclusion.</li>
 128         <li>Using a 14-day moving average makes it clearer. A 100-day rolling period averages out nearly all the specifics from the data.</li>
 129         <li>There's a gap in the data for SF, when the weather station was down (zoom into October 2007 to see it).</li>
 130         <li>The bands around each point indicate average highs and lows.</li>
 131         <li>There is a <em>lot</em> of data in this chart: low, average and high for each city on each day of a three year period &asymp; 6000 data points in all.</li>
 132       </ul>
 133
 134       <p>dygraphs allows the user to explore the data and discover these facts.</p>
 135
 136       <p>For more demos, browse the dygraph <a href="tests/">tests</a>
 137       directory. To see other people who are using dygraphs, check out the <a
 138       href="#gallery">usage gallery</a>.</p>
 139
 140       <h3>Features</h3>
 141       <p>Some of the features of dygraphs:</p>
 142       <ul>
 143         <li>Plots time series without using an external server or Flash</li>
 144         <li>Works in Internet Explorer (using excanvas)</li>
 145         <li>Lightweight (69kb) and responsive</li>
 146         <li>Displays values on mouseover, making interaction easily discoverable</li>
 147         <li>Supports error bands around data series</li>
 148         <li>Interactive zoom</li>
 149         <li>Displays Annotations on the chart</li>
 150         <li>Adjustable averaging period</li>
 151         <li>Can intelligently chart fractions</li>
 152         <li>Customizable click-through actions</li>
 153         <li>Compatible with the Google Visualization API</li>
 154         <li>Intelligent defaults make it easy to use</li>
 155       </ul>
 156
 157       <h2 id="usage">Usage</h2>
 158
 159       <p>To use dygraphs, include the <code><a href="http://github.com/danvk/dygraphs/downloads/">dygraph-combined.js</a></code> JavaScript file and instantiate a <code>Dygraph</code> object.</p>
 160
 161       <p>Here's a basic example to get things started:</p>
 162
 163       <div class="example" style="clear:both;">
 164         <div class="codeblock" style="float:left;width:400px;">
 165           <h3 style="text-align:center">HTML</h3>
 166           <code>
 167   <pre>
 168 &lt;html&gt;
 169 &lt;head&gt;
 170 &lt;script type=&quot;text/javascript&quot;
 171   src=&quot;dygraph-combined.js&quot;&gt;&lt;/script&gt;
 172 &lt;/head&gt;
 173 &lt;body&gt;
 174 &lt;div id=&quot;graphdiv&quot;&gt;&lt;/div&gt;
 175 &lt;script type=&quot;text/javascript&quot;&gt;
 176   g = new Dygraph(
 177
 178     // containing div
 179     document.getElementById(&quot;graphdiv&quot;),
 180
 181     // CSV or path to a CSV file.
 182     &quot;Date,Temperature\n&quot; +
 183     &quot;2008-05-07,75\n&quot; +
 184     &quot;2008-05-08,70\n&quot; +
 185     &quot;2008-05-09,80\n&quot;
 186
 187   );
 188 &lt;/script&gt;
 189 &lt;/body&gt;
 190 &lt;/html&gt;
 191 </pre>
 192           </code>
 193         </div>
 194         <div class="codeoutput" style="float:left;">
 195           <h3 style="text-align:center">OUTPUT</h3>
 196           <div id="graphdiv"></div>
 197           <script type="text/javascript">
 198             g = new Dygraph(
 199
 200               // containing div
 201               document.getElementById("graphdiv"),
 202
 203               // CSV or path to a CSV file.
 204               "Date,Temperature\n" +
 205               "2008-05-07,75\n" +
 206               "2008-05-08,70\n" +
 207               "2008-05-09,80\n"
 208             );
 209           </script>
 210         </div>
 211       </div>
 212
 213       <p style="clear:both">In order to keep this example self-contained, the second parameter is raw CSV data. The dygraphs library parses this data (including column headers), resizes its container to a reasonable default, calculates appropriate axis ranges and tick marks and draws the graph.</p>
 214
 215       <p>In most applications, it makes more sense to include a CSV file instead. If the second parameter to the constructor doesn't contain a newline, 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&amp;monthend=12&amp;yearend=2007&amp;req_city=NA&amp;req_state=NA&amp;req_statename=NA">Weather Underground</a>)</p>
 216
 217       <div class="example" style="clear:both;">
 218         <div class="codeblock" style="float:left;width:400px;">
 219           <h3 style="text-align:center">HTML</h3>
 220           <code>
 221 <pre>
 222 &lt;html&gt;
 223 &lt;head&gt;
 224 &lt;script type=&quot;text/javascript&quot;
 225   src=&quot;dygraph-combined.js&quot;&gt;&lt;/script&gt;
 226 &lt;/head&gt;
 227 &lt;body&gt;
 228 &lt;div id=&quot;graphdiv2&quot;
 229   style=&quot;width:500px; height:300px;&quot;&gt;&lt;/div&gt;
 230 &lt;script type=&quot;text/javascript&quot;&gt;
 231   g2 = new Dygraph(
 232     document.getElementById(&quot;graphdiv2&quot;),
 233     &quot;temperatures.csv&quot;, // path to CSV file
 234     {}          // options
 235   );
 236 &lt;/script&gt;
 237 &lt;/body&gt;
 238 &lt;/html&gt;
 239 </pre>
 240           </code>
 241         </div>
 242         <div class="codeoutput" style="float:left;">
 243           <h3 style="text-align:center">OUTPUT</h3>
 244           <div id="graphdiv2" style="width:500px; height:300px;"></div>
 245           <script type="text/javascript">
 246             g2 = new Dygraph(
 247               document.getElementById("graphdiv2"),
 248               "temperatures.csv",
 249               {}
 250             );
 251           </script>
 252         </div>
 253       </div>
 254
 255       <p style="clear:both;">The file used is <code><a href="temperatures.csv">temperatures.csv</a></code>.</p>
 256
 257       <p>There are a few things to note here:</p>
 258
 259       <ul>
 260         <li>The Dygraph sent off an XHR to get the temperatures.csv file.</li>
 261         <li>The labels were taken from the first line of <code>temperatures.csv</code>, which is <code>Date,High,Low</code>.</li>
 262         <li>The Dygraph automatically chose two different, easily-distinguishable colors for the two data series.</li>
 263         <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>
 264         <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>
 265         <li>The data is very spiky. A moving average would be easier to interpret.</li>
 266       </ul>
 267
 268       <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 <code>rollPeriod</code> option. Here's how it's done:</p>
 269
 270       <div class="example" style="clear:both;">
 271         <div class="codeblock" style="float:left;width:400px;">
 272           <h3 style="text-align:center">HTML</h3>
 273           <code>
 274 <pre>
 275 &lt;html&gt;
 276 &lt;head&gt;
 277 &lt;script type=&quot;text/javascript&quot;
 278   src=&quot;dygraph-combined.js&quot;&gt;&lt;/script&gt;
 279 &lt;/head&gt;
 280 &lt;body&gt;
 281 &lt;div id=&quot;graphdiv3&quot;
 282   style=&quot;width:500px; height:300px;&quot;&gt;&lt;/div&gt;
 283 &lt;script type=&quot;text/javascript&quot;&gt;
 284   g3 = new Dygraph(
 285     document.getElementById(&quot;graphdiv3&quot;),
 286     &quot;temperatures.csv&quot;,
 287     {
 288       rollPeriod: 7,
 289       showRoller: true
 290     }
 291   );
 292 &lt;/script&gt;
 293 &lt;/body&gt;
 294 &lt;/html&gt;
 295 </pre>
 296           </code>
 297         </div>
 298         <div class="codeoutput" style="float:left;">
 299           <h3 style="text-align:center">OUTPUT</h3>
 300           <div id="graphdiv3" style="width:500px; height:300px;"></div>
 301           <script type="text/javascript">
 302             g3 = new Dygraph(
 303               document.getElementById("graphdiv3"),
 304               "temperatures.csv",
 305               {
 306                 rollPeriod: 7,
 307                 showRoller: true
 308               }
 309             );
 310           </script>
 311         </div>
 312       </div>
 313
 314       <p style="clear:both;">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). Also note that we've explicitly set the size of the chart div.</p>
 315
 316       <h2>Error Bars</h2>
 317
 318       <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 <em>&plusmn;n</em> 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. <em>&sigma; = sqrt( (&sigma;<sub>1<sup>2</sup></sub> + &sigma;<sub>2<sup>2</sup></sub> + ... + &sigma;<sub>n<sup>2</sup></sub>) / n )</em></p>
 319
 320       <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 at <a href="twonormals.csv">twonormals.csv</a>.</p>
 321
 322       <div class="example" style="clear:both;">
 323         <div class="codeblock" style="float:left;width:400px;">
 324           <h3 style="text-align:center">HTML</h3>
 325           <code>
 326 <pre>
 327 &lt;html&gt;
 328 &lt;head&gt;
 329 &lt;script type=&quot;text/javascript&quot;
 330   src=&quot;combined.js&quot;&gt;&lt;/script&gt;
 331 &lt;/head&gt;
 332 &lt;body&gt;
 333 &lt;div id=&quot;graphdiv4&quot;
 334   style=&quot;width:480px; height:320px;&quot;&gt;&lt;/div&gt;
 335 &lt;script type=&quot;text/javascript&quot;&gt;
 336   g4 = new Dygraph(
 337     document.getElementById(&quot;graphdiv4&quot;),
 338     &quot;twonormals.csv&quot;,
 339     {
 340       rollPeriod: 7,
 341       showRoller: true,
 342       errorBars: true,
 343       valueRange: [50,125]
 344     }
 345   );
 346 &lt;/script&gt;
 347 &lt;/body&gt;
 348 &lt;/html&gt;
 349 </pre>
 350           </code>
 351         </div>
 352         <div class="codeoutput" style="float:left;">
 353           <h3 style="text-align:center">OUTPUT</h3>
 354           <div id="graphdiv4" style="width:480px; height:320px;"></div>
 355           <script type="text/javascript">
 356             g4 = new Dygraph(
 357               document.getElementById("graphdiv4"),
 358               "twonormals.csv",
 359               {
 360                 rollPeriod: 7,
 361                 showRoller: true,
 362                 errorBars: true,
 363                 valueRange: [50,125]
 364               }
 365             );
 366           </script>
 367         </div>
 368       </div>
 369
 370       <p style="clear:both;">Things to note here:</p>
 371
 372       <ul>
 373         <li>The <strong>errorBars</strong> option affects both the interpretation of the CSV file and the display of the graph. When <strong>errorBars</strong> is set to true, each line is interpreted as <em>YYYYMMDD</em>, <em>A</em>, <em>sigma_A</em>, <em>B</em>, <em>sigma_B</em>, &hellip;</li>
 374         <li>The first line of the CSV file doesn't mention the error columns. In this case, it's just "Date,Series1,Series2".</li>
 375         <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>
 376         <li>The error bars are partially transparent. This can be seen when they overlap one another.</li>
 377       </ul>
 378
 379       <h2 id="ie">Internet Explorer Compatibility</h2>
 380
 381       <p>The dygraphs library relies heavily on the HTML5 <code>&lt;canvas&gt;</code> tag, which Microsoft Internet Explorer did not traditionally support. To use Microsoft's native canvas implementation in IE9, you need to set an HTML5 doctype on your page:</p>
 382
 383 <pre>
 384 &lt;!DOCTYPE html&gt;
 385 </pre>
 386
 387       <p>When IE9 is in HTML5 mode, dygraphs works just like in other modern browsers.</p>
 388
 389       <p>If you want to support previous versions of Internet Explorer (IE6&ndash;IE8), you'll need to include the <a href="http://code.google.com/p/explorercanvas/">excanvas</a> library, which emulates the <code>&lt;canvas&gt;</code> tag using VML. You can add excanvas by including the following snippet:</p>
 390
 391 <pre>
 392 &lt;!DOCTYPE html&gt;
 393 &lt;html&gt;
 394   &lt;head&gt;
 395     &lt;meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7; IE=EmulateIE9"&gt;
 396     &lt;!--[if IE]&gt;&lt;script src="path/to/excanvas.js"&gt;&lt;/script&gt;&lt;![endif]--&gt;
 397   &lt;/head&gt;
 398 </pre>
 399
 400 <p>(This is surprisingly tricky because the HTML5 doctype breaks excanvas in IE8. See <a href="https://groups.google.com/group/dygraphs-users/browse_thread/thread/c60709e04bc7fe5f#">this discussion</a> for details.)</p>
 401
 402     <p>While VML emulation sounds like it would be slow, it works well in practice for most charts.</p>
 403
 404     <p>One common gotcha to look out for: make sure you don't have any trailing commas in parameter lists, e.g.</p>
 405
 406 <pre>
 407 new Dygraph(el, data, {
 408   showRoller: true,  // note trailing comma
 409 })</pre>
 410
 411     <p>Most browsers will ignore the trailing comma, but it will break under IE.</p>
 412
 413     <h2 id="gviz">GViz Data</h2>
 414
 415     <p>The <a
 416       href="http://code.google.com/apis/visualization/documentation/index.html">Google
 417       Visualization API</a> provides a standard interface for describing data.
 418     Once you've specified your data using this API, you can plug in any
 419     GViz-compatible visualization. dygraphs is such a visualization. In
 420     particular, it can be used as a drop-in replacement for the
 421     AnnotatedTimeline visualization used on Google Finance and other sites. To
 422     see how this works, check out the <a href="tests/annotation-gviz.html">gviz
 423       annotation demo.</a></p>
 424
 425     <p>For a simple demonstration of how to use dygraphs a GViz visualization, see <a href="http://danvk.org/dygraphs/tests/gviz.html">http://danvk.org/dygraphs/tests/gviz.html</a>. dygraphs can also be used as a GViz gadget. This allows it to be embedded inside of a Google Spreadsheet. For a demonstration of this, see <a   href="http://spreadsheets.google.com/ccc?key=0Anx1yCqeL8YUdDR1c3pPREhraGhkWmdhaURjOXRncXc&amp;hl=en">this spreadsheet</a>. The URL for the gadget is <code><a href="http://danvk.org/dygraphs/gadget.xml">http://danvk.org/dygraphs/gadget.xml</a></code>.</p>
 426
 427     <p>Here's an example of a published gviz gadget using dygraphs:</p>
 428
 429     <script src="http://spreadsheets.google.com/gpub?url=http%3A%2F%2Fkb8jbn8l90ocl9n4b14jrcvp61ceqis5.spreadsheets.gmodules.com%2Fgadgets%2Fifr%3Fup__table_query_url%3Dhttp%253A%252F%252Fspreadsheets.google.com%252Ftq%253Frange%253DA1%25253AC31%2526headers%253D-1%2526key%253D0Anx1yCqeL8YUdDR1c3pPREhraGhkWmdhaURjOXRncXc%2526gid%253D0%2526pub%253D1%26up__table_query_refresh_interval%3D300%26url%3Dhttp%253A%252F%252Fdanvk.org%252Fdygraphs%252Fgadget.xml%253Fnocache&height=215&width=530"></script>
 430
 431     <h2 id="baseball">Charting Fractions</h2>
 432
 433     <p>Situations often arise where you want to plot fractions, e.g. the fraction of respondents in a poll who said they'd vote for candidate X or the number of hits divided by at bats (baseball's batting average). Fractions require special treatment for two main reasons:</p>
 434
 435     <ul>
 436       <li>The average of <code>a1/b1</code> and <code>a2/b2</code> is <code>(a1+a2)/(b1+b2)</code>, not <code>(a1/b1 + a2/b2)/2</code>.</li>
 437       <li>The normal approximation is not always applicable and more sophisticated confidence intervals (e.g. the <a href="http://en.wikipedia.org/wiki/Binomial_proportion_confidence_interval">Wilson confidence interval</a>) must be employed to avoid ratios that exceed 100% or go below 0%.</li>
 438     </ul>
 439
 440     <p>Fortunately, dygraphs handles both of these for you! Here's a chart and the command that generated it:</p>
 441
 442     <div style="width:750px; text-align:center; font-weight: bold; font-size: 125%;">Batting Average for Ichiro Suzuki vs. Mariners (2004)</div>
 443     <div id="baseballdiv" style="width:750px; height:300px;"></div>
 444     <script type="text/javascript">
 445       new Dygraph(
 446         document.getElementById("baseballdiv"),
 447         "suzuki-mariners.txt",
 448         {
 449           fractions: true,
 450           errorBars: true,
 451           showRoller: true,
 452           rollPeriod: 15
 453         }
 454       );
 455     </script>
 456
 457     <p>Command:</p>
 458 <pre>
 459   new Dygraph(
 460     document.getElementById(&quot;baseballdiv&quot;),
 461     &quot;suzuki-mariners.txt&quot;,
 462     {
 463       fractions: true,
 464       errorBars: true,
 465       showRoller: true,
 466       rollPeriod: 15
 467     }
 468   );
 469 </pre>
 470
 471     <p>The <code>fractions</code> option indicates that the values in each column should be parsed as fractions (e.g. "1/2" instead of "0.5"). The <code>errorBars</code> option indicates that we'd like to see a confidence interval around each data point. By default, when <code>fractions</code> is set, you get a Wilson confidence interval. If you look carefully at the chart, you can see that the error bars are asymmetric.</p>
 472
 473     <p>A couple things to notice about this chart:</p>
 474
 475     <ul>
 476       <li>The error bars for Ichiro's batting average are larger than for the Mariners', since he has far fewer at bats than his team.</li>
 477       <li>dygraphs makes it easy to see "batting average over the last 30 games". This is ordinarily quite difficult to compute. It makes it clear where the "hot" and "cold" part of Suzuki's season were.</li>
 478       <li>If you set the averaging period to something large, like 200, you'll see the team's and player's batting average through that game. The final number is the overall batting average for the season.</li>
 479       <li>Where the error bars do not overlap, we can say with 95% confidence that the series differ. There is a better than 95% chance that Ichiro was a better hitter than his team as a whole in 2004, the year he won the batting title.</li>
 480     </ul>
 481
 482     <h2 id="stock">One last demo</h2>
 483
 484     <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>
 485
 486     <div id="dow_chart" style="width:750px; height:350px;"></div>
 487     <p><b>Display: </b>
 488     <input type=checkbox id=0 onClick="stockchange(this)" checked>
 489     <label for="0"> Nominal</label>
 490     <input type=checkbox id=1 onClick="stockchange(this)" checked>
 491     <label for="1"> Real</label>
 492     <input type=checkbox id=ann onClick="annotationschange(this)" checked>
 493     <label for="ann"> Annotations</label>
 494     </p>
 495
 496     <script type="text/javascript">
 497       var stock_annotations = [
 498         {
 499           series: "Real",
 500           x: "1929-08-15",
 501           shortText: "A",
 502           text: "1929 Stock Market Peak"
 503         },
 504         {
 505           series: "Nominal",
 506           x: "1987-08-15",
 507           shortText: "B",
 508           text: "1987 Crash"
 509         },
 510         {
 511           series: "Nominal",
 512           x: "1999-12-15",
 513           shortText: "C",
 514           text: "1999 (.com) Peak"
 515         },
 516         {
 517           series: "Nominal",
 518           x: "2007-10-15",
 519           shortText: "D",
 520           text: "All-Time Market Peak"
 521         }
 522       ];
 523
 524     // From http://www.econstats.com/eqty/eq_d_mi_3.csv
 525       stockchart = new Dygraph(
 526         document.getElementById('dow_chart'),
 527         "dow.txt",
 528         {
 529           showRoller: true,
 530           customBars: true,
 531           labelsKMB: true,
 532           drawCallback: function(g, is_initial) {
 533             if (!is_initial) return;
 534             g.setAnnotations( stock_annotations );
 535           }
 536         }
 537       );
 538
 539       function stockchange(el) {
 540         stockchart.setVisibility(el.id, el.checked);
 541       }
 542
 543       function annotationschange(el) {
 544         if (el.checked) {
 545           stockchart.setAnnotations(stock_annotations);
 546         } else {
 547           stockchart.setAnnotations([]);
 548         }
 549       }
 550     </script>
 551 <!--
 552
 553 Here is a script to regenerate the Dow Jones plot:
 554
 555 # Get unadjusted DJIA data in a nice format:
 556 curl -O http://www.econstats.com/eqty/eq_d_mi_3.csv
 557 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
 558
 559 # Fetch and format the CPI data:
 560 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
 561 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-$2\t/g' > cpi-u.tsv
 562
 563 # Merge:
 564 join -t'     ' cpi-u.tsv monthly-djia.tsv > annotated-djia.tsv
 565 perl -ne 'BEGIN{print "Month,Nominal,Real\n"} chomp; ($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
 566
 567 -->
 568
 569     <h2 id="options">Other Options</h2>
 570
 571     <p>In addition to the options mentioned above (<code>showRoller</code>, <code>rollPeriod</code>, <code>errorBars</code>, <code>valueRange</code>), there are <i>many</i> others.</p>
 572
 573     <p>For a full list, see the <a href="options.html">Dygraphs Options Reference</a> page.</p>
 574
 575     <h2>Common Gotchas</h2>
 576
 577     <p>Here are a few problems that I've frequently run into while using the dygraphs library.</p>
 578
 579     <ul>
 580       <li>If your chart doesn't display, be sure to check your browser's JavaScript error console. dygraphs makes every attempt to log errors and warnings, and these can often guide you in the right direction.</li>
 581       <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>
 582       <li>Make sure your CSV files are in the correct format. They must be of the form <code>YYYYMMDD, series1, series2, </code>&hellip; . And if you set the <code>errorBars</code> property, make sure you alternate data series and standard deviations.</li>
 583       <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 <code>align = center</code> set.</li>
 584       <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>
 585       <li>Make sure you don't have any trailing commas in your call to the Dygraph constructor or in the options parameter. Firefox, Chrome and Safari ignore these but they can cause a graph to not display in Internet Explorer.</li>
 586     </ul>
 587
 588     <h2 id="gwt">GWT Compatibility</h2>
 589     <p>There is currently no GWT wrapper around Dygraphs, however there is a class that can be used to easily load Dygraphs into the browser.  To use it, include the generated dygraph-gwt.jar file in your classpath and add the following line to your GWT module:</p>
 590
 591 <pre>
 592 &lt;inherits name=&quot;org.danvk.dygraphs&quot;/&gt;
 593 </pre>
 594
 595     <p>Call org.danvk.Dygraphs.install() when your application starts to install the JavaScript code into the browser.  You can use <a href="http://code.google.com/webtoolkit/doc/latest/DevGuideCodingBasicsJSNI.html">JSNI</a> to call Dygraphs from your GWT code, as in the example below.  The example uses the <a href="http://code.google.com/p/gwt-google-apis/wiki/VisualizationGettingStarted">Visualization API for GWT</a> and the <a href="#gviz">Dygraphs GViz API.</a></p>
 596
 597 <pre>
 598 public static native JavaScriptObject drawDygraph(
 599     Element element, DataTable dataTable, double minY, double maxY) /*-{
 600   var chart = new $wnd.Dygraph.GVizChart(element);
 601   chart.draw(dataTable,
 602     {
 603       valueRange: [minY, maxY]
 604     });
 605   return chart;
 606 }-*/;
 607 </pre>
 608
 609     <a name="gallery" />
 610     <h2>Usage Gallery</h2>
 611     <p>Since its public release in late 2009, dygraphs has found many users
 612     across the web. This is a small collection of the uses that we know about.
 613     If you're using dygraphs, please send <a
 614     href="mailto:dan@dygraphs.com">Dan</a> a link and he'll add it to this
 615     list.</p>
 616
 617     <p>dygraphs was originally developed at Google and has found wide use on
 618     internal dashboards and servers there. There are also a few uses of
 619     dygraphs on public Google products:</p>
 620
 621     <ul class='padded-list'>
 622     <li><a href="http://www.google.com/trends/correlate/search?e=id:20xKcnNqHrk&t=weekly">Google Correlate</a><br/>
 623     <span class="desc">Uses dygraphs for time series visualization. Mostly a standard configuration, with just a few tweaks to match Google style.</span></li>
 624
 625     <li><a href="http://www.google.com/trends/correlate/draw?p=us">Google Correlate - Search by Drawing</a><br/>
 626     <span class="desc">This is a highly customized configuration which lets the user draw a time series. Based on <a href="tests/drawing.html">this demo</a>.</span></li>
 627
 628     <li><a href="https://www.google.com/latitude/b/0/history/manage">Google Latitude History Dashboard</a><br/>
 629     <span class="desc">Uses mouse interaction callbacks to synchronize time series points with markers on a Google Map.</span></li>
 630     </ul>
 631
 632     <p>dygraphs has also found use in other organizations:</p>
 633
 634     <ul class='padded-list'>
 635   <li><a
 636     href="http://iswa.ccmc.gsfc.nasa.gov:8080/IswaSystemWebApp/index.jsp?i_1=388&l_1=99&t_1=316&w_1=800&h_1=400&s_1=0!3!0!ACE.B_x!ACE.B_y!ACE.B_z!">Integrated
 637     Space Weather Analysis System</a> (NASA)<br/>
 638   <span class="desc">&ldquo;We use [dygraphs] in the Integrated Space Weather
 639     Analysis System available from the Space Weather Laboratory at NASA Goddard
 640     Space Flight Center. It works quite well for time series data from various
 641     missions and simulations that we store.&rdquo;</span></li>
 642
 643
 644   <li><a href="http://www.eutelsat.fr">Eutelsat</a><br/>
 645   <span class="desc">&ldquo;Eutelsat uses dygraphs for charting spacecraft
 646     telemetry for a fleet of 25 geostationary satellites. The spacecraft
 647     engineers are very happy with it.  All satellite combined are producing
 648     about 200 millions unique data points per day so we really appreciate the
 649     excellent performance of dygraphs.&rdquo;</span></li>
 650
 651   <li><a href="http://www.10gen.com/mongodb-monitoring-service">10gen MongoDB
 652     Monitoring Service</a><br/>
 653   <span class="desc">A free monitoring service for MongoDB from 10gen (the
 654     creators of MongoDB). Used by thousands of servers and users. Makes use of
 655     <a href="tests/synchronize.html">synchronized charts</a> to display many
 656     quantities simultaneously.</span></li>
 657
 658     <li><a href="http://toolserver.org/~dartar/moodbar/">Wikimedia Foundation - Moodbar data dashboard</a><br/>
 659     <span class="desc">dygraphs is used internally at Wikimedia as a handy solution to monitor the
 660     results of a bunch of small experiments.</span></li>
 661
 662
 663     <li><a href="http://www.socib.es/jwebchart/?file=http://thredds.socib.es/thredds/dodsC/mooring/weather_station/mobims_calamillor-scb_met001/L1/dep0001_mobims-calamillor_scb-met001_L1_latest.nc">Jwebchart</a><br/>
 664     <span class="desc">
 665     jWebChart is a stand-alone and Thredds' embedded plotting system for
 666     netCDF files. NetCDF is a common standard for the storage and
 667     distribution of scientific data.
 668     </span></li>
 669
 670     <li><a href="http://ngrams.cavorite.com/">n-gramas - Explore las tendencias en los artículos periodísticos de Colombia.</a><br/>
 671
 672
 673     <span class="desc">(English: "Explore trends in newspaper articles of
 674     Colombia"). dygraphs is used for displaying the results of this n-grams
 675     viewer.  Uses an extension for exporting the plots as PNG images
 676     (<a href="http://cavorite.com/labs/js/dygraphs-export/">[1]</a>, <a href="https://github.com/cavorite/dygraphs">[2]</a>).
 677     </span></li>
 678
 679     </ul>
 680
 681     <p>Are you using dygraphs? Please let <a href="mailto:dan@dygraphs.com">Dan</a> know and he'll add your link here!</p>
 682
 683
 684     <h2 id="policy">Data Policy</h2>
 685     <p>dygraphs is purely client-side JavaScript. It does not send your data to any servers &ndash; the data is processed entirely in the client's browser.</p>
 686
 687     <p style="font-size:0.8em">Created May 9, 2008 by <a href=mailto:danvdk@gmail.com>Dan Vanderkam</a></p>
 688   </div>
 689
 690 </body>
 691 </html>