3 <title>dygraphs JavaScript Library
</title>
5 <script type=
"text/javascript" src=
"excanvas.js"></script>
7 <script type=
"text/javascript" src=
"dygraph-combined.js"></script>
8 <style type=
"text/css">
14 border-collapse: collapse;
16 .thinborder td, .thinborder th {
26 <p><span style=
"font-size:28pt;">dygraphs JavaScript Library
</span><br/>
27 <a href=
"http://code.google.com/p/dygraphs/">code.google.com/p/dygraphs
</a></p>
30 <p>The dygraphs JavaScript library produces produces interactive, zoomable charts of time series.
</p>
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>
41 <li>Compatible with the Google Visualization API
</li>
46 <li>Requires Firefox
1.5+ or Safari/WebKit
1.3+.
</li>
47 <li>Internet Explorer is poorly supported.
</li>
51 <font size=-
1>(Mouse over to highlight individual values. Click and drag to zoom. Double-click to zoom out.)
</font><br/>
53 <div id=
"demodiv" style=
"width:480px; height:320px;"></div>
55 <div id=
"status" style=
"width:200px; font-size:0.8em; padding-top:5px;"></div>
58 <script type=
"text/javascript">
60 document.getElementById(
"demodiv"),
62 var zp = function(x) { if (x <
10) return
"0"+x; else return x; };
63 var r =
"date,parabola,line,another line,sine wave\n";
64 for (var i=
1; i<=
31; i++) {
65 r +=
"200610" + zp(i);
66 r +=
"," +
10*(i*(
31-i));
68 r +=
"," +
10*(
250 -
8*i);
69 r +=
"," +
10*(
125 +
125 * Math.sin(
0.3*i));
77 labelsDiv: document.getElementById('status'),
78 labelsSeparateLines: true,
80 colors: [
"hsl(180,60,50)",
83 "rgba(50,50,200,0.4)"],
84 padding: {left:
40, right:
30, top:
15, bottom:
15},
89 <p>For more demos, browse the dygraph
<a href=
"tests/">tests
</a> directory.
</p>
93 <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:
95 <pre>./generate-combined.sh
</pre>
97 <p>The combined JS file is now in
<code>dygraph-combined.js
</code>. Here's a basic example to get things started:
</p>
101 <td rowspan=
2><img src=arrow.gif
/></td>
107 <script
type=
"text/javascript"
108 src=
"combined.js"></script
>
111 <div
id=
"graphdiv"></div
>
112 <script
type=
"text/javascript">
115 document.getElementById(
"graphdiv"),
116 // CSV or path to a CSV file.
117 "Date,Temperature\n" +
127 <div id=
"graphdiv"></div>
128 <script type=
"text/javascript">
130 document.getElementById(
"graphdiv"), // containing div
131 "Date,Temperature\n" + // CSV or path to a CSV file.
139 <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>
143 <td rowspan=
2><img src=arrow.gif
/></td>
149 <script
type=
"text/javascript"
150 src=
"combined.js"></script
>
153 <div
id=
"graphdiv"
154 style=
"width:500px; height:300px;"></div
>
155 <script
type=
"text/javascript">
157 document.getElementById(
"graphdiv"),
158 "temperatures.csv", // path to CSV file
166 <div id=
"graphdiv2" style=
"width:500px; height:300px;"></div>
167 <script type=
"text/javascript">
169 document.getElementById(
"graphdiv2"),
170 "temperatures.csv", {}
175 <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>
178 <li>The Dygraph sent off an XHR to get the temperatures.csv file.
</li>
179 <li>The labels were taken from the first line of
<code>temperatures.csv
</code>, which is
<code>Date,High,Low
</code>.
</li>
180 <li>The Dygraph automatically chose two different, easily-distinguishable colors for the two data series.
</li>
181 <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>
182 <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>
183 <li>The data is very spiky. A moving average would be easier to interpret.
</li>
186 <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>
190 <td rowspan=
2><img src=arrow.gif
/></td>
196 <script
type=
"text/javascript"
197 src=
"combined.js"></script
>
200 <div
id=
"graphdiv"
201 style=
"width:500px; height:300px;"></div
>
202 <script
type=
"text/javascript">
204 document.getElementById(
"graphdiv"),
215 <div id=
"graphdiv3" style=
"width:500px; height:300px;"></div>
216 <script type=
"text/javascript">
218 document.getElementById(
"graphdiv3"),
227 <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>
230 <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>
232 <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>
236 <td rowspan=
2><img src=arrow.gif
/></td>
242 <script
type=
"text/javascript"
243 src=
"combined.js"></script
>
246 <div
id=
"graphdiv"
247 style=
"width:600px; height:300px;"
249 <script
type=
"text/javascript">
250 $ = document.getElementById;
265 <div id=
"graphdiv4" style=
"width:600px; height:300px;"></div>
266 <script type=
"text/javascript">
267 $ = document.getElementById;
269 document.getElementById(
"graphdiv4"),
274 valueRange: [
50,
125]
280 <p>Things to note here:
</p>
282 <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>
283 <li>The first line of the CSV file doesn't mention the error columns. In this case, it's just
"Date,Series1,Series2".
</li>
284 <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>
285 <li>The error bars are partially transparent. This can be seen when they overlap one another.
</li>
288 <h2>One last demo
</h2>
290 <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>
292 <div id=dow_chart
style=
"width:900px; height:350px;"></div>
293 <script type=
"text/javascript">
294 // From http://www.econstats.com/eqty/eq_d_mi_3.csv
296 document.getElementById('dow_chart'),
302 padding: {left:
30, right:
30, top:
5, bottom:
5}
307 Here is a script to regenerate the Dow Jones plot:
309 # Get unadjusted DJIA data in a nice format:
310 curl -O http://www.econstats.com/eqty/eq_d_mi_3.csv
311 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
313 # Fetch and format the CPI data:
314 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
315 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
318 join -t' ' cpi-u.tsv monthly-djia.tsv
> annotated-djia.tsv
319 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
324 <h2>Other Options
</h2>
325 <p>These are the options that can be passed in through the optional third parameter of the Dygraph constructor. To see demonstrations of many of these options, browse the
<a href=
"tests/">dygraphs tests
</a> directory.
</p>
327 <table class=thinborder width=
900>
328 <tr><th>Name
</th><th>Sample Value
</th><th>Description
</th></tr>
330 <td><b>includeZero
</b></td>
331 <td><code>true, false
</code></td>
332 <td>Usually, dygraphs will use the range of the data plus some padding to
333 set the range of the y-axis. If this option is set, the y-axis will always
334 include zero, typically as the lowest value. This can be used to avoid
335 exaggerating the variance in the data.
</td>
339 <td><b>rollPeriod
</b></td>
340 <td><code>7</code></td>
341 <td>Number of days over which to average data. Discussed extensively above.
</td>
345 <td><b>showRoller
</b></td>
346 <td><code>true
</code></td>
347 <td>Should the rolling average period text box be shown? Default is false.
</td>
351 <td><b>colors
</b></td>
352 <td><code>['red',
'#
00FF00']
</code></td>
353 <td>List of colors for the data series. These can be of the form
"#AABBCC"
354 or
"rgb(255,100,200)" or
"yellow", etc. If not specified, equally-spaced
355 points around a color wheel are used.
</td>
359 <td><b>colorSaturation
</b></td>
360 <td><code>1.0</code></td>
361 <td>If
<b>colors
</b> is not specified, saturation of the
362 automatically-generated data series colors. (
0.0-
1.0, default:
367 <td><b>colorValue
</b></td>
368 <td><code>0.5</code></td>
369 <td>If colors is not specified, value of the data series colors, as in
370 hue/saturation/value. (
0.0-
1.0, default
0.5)
</td>
374 <td><b>clickCallback
</b></td>
375 <td><code>function(e,date){ alert(date); }
</code></td>
376 <td>A function to call when a data point is clicked. The function should take
377 two arguments, the event object for the click and the date that was
378 clicked. (default null)
</td>
382 <td><b>zoomCallback
</b></td>
383 <td><code>function(minDate,maxDate) {}
</code></td>
384 <td>A function to call when the zoom window is changed (either by zooming
385 in or out). minDate and maxDate are millis since epoch.
</td>
389 <td><b>strokeWidth
</b></td>
390 <td><code>2.0</code></td>
391 <td>Width of the data lines. This can be used to increase the contrast or
392 some graphs. (default
1.0)
</td>
396 <td><b>dateWindow
</b></td>
397 <td><code>[Date.parse('
2006-
01-
01'),
<br/>
398 (new
Date()).valueOf()]
</code></td>
399 <td>Initially zoom in on a section of the graph. Is of the form [earliest,
400 latest], where earliest/latest are millis since epoch. By default, the
401 full range of the input is shown.
</td>
405 <td><b>valueRange
</b></td>
406 <td><code>[
10,
110]
</code></td>
407 <td>Explicitly set the vertical range of the graph to [low, high]. By
408 default, some clever heuristics are used (see above).
</td>
412 <td><b>labelsSeparateLines
</b></td>
413 <td><code>true
</code></td>
414 <td>Put
<br/
> between lines in the label string. Often used in
415 conjunction with
<b>labelsDiv
</b>. (default false)
</td>
419 <td><b>labelsDiv
</b></td>
420 <td><code>document.getElementById('foo')
</code></td>
421 <td>Show data labels in an external div, rather than on the graph. (default
426 <td><b>labelsKMB
</b></td>
427 <td><code>true
</code></td>
428 <td>Show K/M/B for thousands/millions/billions on y-axis (default
433 <td><b>labelsDivWidth
</b></td>
435 <td>Width (in pixels) of the div which shows information on the
436 currently-highlighted points.
</td>
440 <td><b>labelsDivStyles
</b></td>
442 <td>Additional styles to apply to the currently-highlighted points div. For
443 example, { 'font-weigth': 'bold' } will make the labels bold.
</td>
447 <td><b>highlightCircleSize
</b></td>
448 <td><code>3</code></td>
449 <td>Size (in pixels) of the dot drawn over highlighted points (default
3).
</td>
453 <td><b>drawPoints
</b></td>
454 <td><code>false
</code></td>
455 <td>Draw a small dot at each point, in addition to a line going through
456 the point. This makes the individual data points easier to see, but can
457 increase visual clutter in the chart. Default: false
</td>
461 <td><b>pointSize
</b></td>
462 <td><code>1.0</code></td>
463 <td>The size of the dot to draw on each point in pixels (see
464 drawPoints). A dot is always drawn when a point is
"isolated", i.e.
465 there is a missing point on either side of it. This also controls the
466 size of those dots.
</td>
470 <td><b>pixelsPerXLabel
</b>,
<b>pixelsPerYLabel
</b></td>
472 <td>Number of pixels to require between each x- and y-label. Larger values
473 will yield a sparser axis with fewer ticks. Defaults:
60 (x-axis),
30
478 <td><b>xAxisLabelWidth
</b>,
<b>yAxisLabelWidth
</b></td>
480 <td>Width (in pixels) of the x- and y-axis labels.
</td>
484 <td><b>axisLabelFontSize
</b></td>
486 <td>Size of the font (in pixels) to use in the axis labels, both x- and
491 <td><b>rightGap
</b></td>
493 <td>Number of pixels to leave blank at the right edge of the Dygraph. This
494 makes it easier to highlight the right-most data point.
</td>
498 <td><b>errorBars
</b></td>
499 <td><code>false
</code></td>
500 <td>Does the data contain standard deviations? Setting this to true alters
501 the input format (see above). (default false)
</td>
505 <td><b>sigma
</b></td>
507 <td>When errorBars is set, shade this many standard deviations above/below
512 <td><b>fractions
</b></td>
514 <td>When set, attempt to parse each cell in the CSV file as
"a/b", where a
515 and b are integers. The ratio will be plotted. This allows computation of
516 Wilson confidence intervals (see below).
</td>
520 <td><b>wilsonInterval
</b></td>
522 <td>Use in conjunction with the
"fractions" option. Instead of plotting +/-
523 N standard deviations, dygraphs will compute a Wilson confidence interval
524 and plot that. This has more reasonable behavior for ratios close to
0 or
529 <td><b>customBars
</b></td>
531 <td>When set, parse each CSV cell as
"low;middle;high". Error bars will be
532 drawn for each point between low and high, with the series itself going
537 <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>
539 <h2>Common Gotchas
</h2>
540 <p>Here are a few problems that I've frequently run into while using the
541 dygraphs library.
</p>
544 <li>Make sure your CSV files are readable! If your graph isn't showing up,
545 the XMLHttpRequest for the CSV file may be failing. You can determine whether
546 this is the case using tools like
<a
547 href=
"http://www.getfirebug.com/">Firebug
</a>.
</li>
549 <li>Make sure your CSV files are in the correct format. They must be of the
550 form
<code>YYYYMMDD,series1,series2,...
</code>. And if you set the
551 <code>errorBars
</code> property, make sure you alternate data series and
552 standard deviations.
</li>
554 <li>dygraphs are not happy when placed inside a
<code><center
></code>
555 tag. This applies to the CSS
<code>text-align
</code> property as well. If you
556 want to center a Dygraph, put it inside a table with
"align=center"
559 <li>Don't set the
<code>dateWindow
</code> property to a date. It expects
560 milliseconds since epoch, which can be obtained from a JavaScript Date
561 object's valueOf method.
</li>
565 <p>dygraphs is purely client-side JavaScript. It does not send your data to any
566 servers -- the data is processed entirely in the client's browser.
</p>
568 <p><font size=-
1>Created May
9,
2008 by
<a href=mailto:danvdk@gmail.com
>Dan Vanderkam
</a></font></p>
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