HTML
+
+
+<html>
+<head>
+<script type="text/javascript"
+ src="dygraph-combined.js"></script>
+</head>
+<body>
+<div id="graphdiv"></div>
+<script type="text/javascript">
+ g = new Dygraph(
-./generate-combined.sh
+ // containing div
+ document.getElementById("graphdiv"),
-The combined JS file is now in dygraph-combined.js. Here's a basic example to get things started:
+ // CSV or path to a CSV file.
+ "Date,Temperature\n" +
+ "2008-05-07,75\n" +
+ "2008-05-08,70\n" +
+ "2008-05-09,80\n"
-
- HTML
- 
Output
-
+ );
+</script>
+</body>
+</html>
+
+
+
+
+ OUTPUT
+
+
+
+
+
+ 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.
+
+ 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 "file:///". Here's an example: (data from Weather Underground)
+
+
+
+ HTML
+
+
<html>
<head>
-<script type="text/javascript" src="combined.js"></script>
+<script type="text/javascript"
+ src="dygraph-combined.js"></script>
</head>
<body>
-<div id="graphdiv" style="width:400px; height:300px;"></div>
-<script type="text/javascript">
- g = new DateGraph(
- document.getElementById("graphdiv"), // containing div
- function() { // function or path to CSV file.
- return "20080507,75\n" +
- "20080508,70\n" +
- "20080509,80\n";
- },
- [ "Temperature" ], // names of data series
- {} // additional options (see below)
- );
+<div id="graphdiv2"
+ style="width:500px; height:300px;"></div>
+<script type="text/javascript">
+ g2 = new Dygraph(
+ document.getElementById("graphdiv2"),
+ "temperatures.csv", // path to CSV file
+ {} // options
+ );
</script>
</body>
</html>
-
-
-
-
-
-In order to keep this example self-contained, the second parameter is a function that returns CSV data. These lines must begin with a date in the form YYYYMMDD. 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 DateGraph 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 "file:///". Here's an example: (data from Weather Underground)
-
-
- HTML
- Output
-
+
+
+
+ OUTPUT
+
+
+
+
+
+ The file used is temperatures.csv.
+
+ There are a few things to note here:
+
+
+ - The Dygraph sent off an XHR to get the temperatures.csv file.
+ - The labels were taken from the first line of
temperatures.csv, which is Date,High,Low.
+ - The Dygraph automatically chose two different, easily-distinguishable colors for the two data series.
+ - The labels on the x-axis have switched from days to months. If you zoom in, they'll switch to weeks and then days.
+ - 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.
+ - The data is very spiky. A moving average would be easier to interpret.
+
+
+ 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 rollPeriod option. Here's how it's done:
+
+
+
+ HTML
+
+
<html>
<head>
-<script type="text/javascript" src="combined.js"></script>
+<script type="text/javascript"
+ src="dygraph-combined.js"></script>
</head>
<body>
-<div id="graphdiv" style="width:600px; height:300px;"></div>
-<script type="text/javascript">
- g = new DateGraph(
- document.getElementById("graphdiv"),
- "temperatures.csv", // path to CSV file
- null, // labels in top line of CSV file
- {}
- );
+<div id="graphdiv3"
+ style="width:500px; height:300px;"></div>
+<script type="text/javascript">
+ g3 = new Dygraph(
+ document.getElementById("graphdiv3"),
+ "temperatures.csv",
+ {
+ rollPeriod: 7,
+ showRoller: true
+ }
+ );
</script>
</body>
</html>
-
-
-
-
-
-Click here to view the temperatures.csv file. There are a few things to note here:
-
-
- - Because the third parameter to the DateGraph constructor was
null, the labels were taken from the first line of the data instead. The first line of temperatures.csv is Date,High,Low.
- - DateGraph automatically chose two different, easily-distinguishable colors for the two data series.
- - The labels on the x-axis have switched from days to months. If you zoom in, they'll switch to weeks and then days.
- - 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, but in this case the vertical range is way too large.
- - The data is very spiky. A moving average would be easier to interpret.
-
-
-These last two problems can be fixed by specifying the appropriate options in the fourth parameter to the DateGraph constructor. To set the number of days for a moving average, use the rollPeriod option. To set the range of the y-axis, use the valueRange option. Here's how it's done:
-
-
- HTML
- Output
-
+
+
+
+ OUTPUT
+
+
+
+
+
+ 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.
+
+ Error Bars
+
+ 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 ±n 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. σ = sqrt( (σ12 + σ22 + ... + σn2) / n )
+
+ Here's a demonstration. There are two data series. One is N(100,10) with a standard deviation of 10 specified at each point. The other is N(80,20) with a standard deviation of 20 specified at each point. The CSV file was generated using Octave and can be viewed at twonormals.csv.
+
+
+
+ HTML
+
+
<html>
<head>
-<script type="text/javascript" src="combined.js"></script>
+<script type="text/javascript"
+ src="combined.js"></script>
</head>
<body>
-<div id="graphdiv" style="width:600px; height:300px;"></div>
-<script type="text/javascript">
- g = new DateGraph(
- document.getElementById("graphdiv"),
- "temperatures.csv", null,
- { rollPeriod: 7,
- valueRange: [25, 100]
- }
- );
+<div id="graphdiv4"
+ style="width:480px; height:320px;"></div>
+<script type="text/javascript">
+ g4 = new Dygraph(
+ document.getElementById("graphdiv4"),
+ "twonormals.csv",
+ {
+ rollPeriod: 7,
+ showRoller: true,
+ errorBars: true,
+ valueRange: [50,125]
+ }
+ );
</script>
</body>
</html>
-
-
-
+
+
+
+ Things to note here:
+
+
+ - The errorBars option affects both the interpretation of the CSV file and the display of the graph. When errorBars is set to true, each line is interpreted as YYYYMMDD, A, sigma_A, B, sigma_B, …
+ - The first line of the CSV file doesn't mention the error columns. In this case, it's just "Date,Series1,Series2".
+ - 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.
+ - The error bars are partially transparent. This can be seen when they overlap one another.
+
+
+ Internet Explorer Compatibility
+
+ The dygraphs library relies heavily on the HTML5 <canvas> 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:
+
+
+<!DOCTYPE html>
+
+
+ When IE9 is in HTML5 mode, dygraphs works just like in other modern browsers.
+
+ If you want to support previous versions of Internet Explorer (IE6–IE8), you'll need to include the excanvas library, which emulates the <canvas> tag using VML. You can add excanvas by including the following snippet:
+
+
+<!DOCTYPE html>
+<html>
+ <head>
+ <meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7; IE=EmulateIE9">
+ <!--[if IE]><script src="path/to/excanvas.js"></script><![endif]-->
+ </head>
+
+
+(This is surprisingly tricky because the HTML5 doctype breaks excanvas in IE8. See this discussion for details.)
+
+ While VML emulation sounds like it would be slow, it works well in practice for most charts.
+
+ One common gotcha to look out for: make sure you don't have any trailing commas in parameter lists, e.g.
+
+
+new Dygraph(el, data, {
+ showRoller: true, // note trailing comma
+})
+
+ Most browsers will ignore the trailing comma, but it will break under IE.
+
+ GViz Data
+
+ The Google
+ Visualization API provides a standard interface for describing data.
+ Once you've specified your data using this API, you can plug in any
+ GViz-compatible visualization. dygraphs is such a visualization. In
+ particular, it can be used as a drop-in replacement for the
+ AnnotatedTimeline visualization used on Google Finance and other sites. To
+ see how this works, check out the gviz
+ annotation demo.
+
+ For a simple demonstration of how to use dygraphs a GViz visualization, see http://danvk.org/dygraphs/tests/gviz.html. 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 this spreadsheet. The URL for the gadget is http://danvk.org/dygraphs/gadget.xml.
+
+ Here's an example of a published gviz gadget using dygraphs:
+
+
+
+ Charting Fractions
+
+ 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:
+
+
+ - The average of
a1/b1 and a2/b2 is (a1+a2)/(b1+b2), not (a1/b1 + a2/b2)/2.
+ - The normal approximation is not always applicable and more sophisticated confidence intervals (e.g. the Wilson confidence interval) must be employed to avoid ratios that exceed 100% or go below 0%.
+
+
+ Fortunately, dygraphs handles both of these for you! Here's a chart and the command that generated it:
+
+ Batting Average for Ichiro Suzuki vs. Mariners (2004)
+
+
+
+ Command:
+
+ new Dygraph(
+ document.getElementById("baseballdiv"),
+ "suzuki-mariners.txt",
+ {
+ fractions: true,
+ errorBars: true,
+ showRoller: true,
+ rollPeriod: 15
+ }
+ );
+
+
+ The fractions option indicates that the values in each column should be parsed as fractions (e.g. "1/2" instead of "0.5"). The errorBars option indicates that we'd like to see a confidence interval around each data point. By default, when fractions is set, you get a Wilson confidence interval. If you look carefully at the chart, you can see that the error bars are asymmetric.
+
+ A couple things to notice about this chart:
+
+
+ - The error bars for Ichiro's batting average are larger than for the Mariners', since he has far fewer at bats than his team.
+ - 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.
+ - 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.
+ - 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.
+
+
+ One last demo
+
+ 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.
+
+
+ Display:
+
+
+
+
+
+
+
+
+
-
+ }
+ );
-A rolling average can always be set using the text box in the lower left-hand corner of the graph.
+ function stockchange(el) {
+ stockchart.setVisibility(el.id, el.checked);
+ }
-Error Bars
-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 +/-n sigma band will be drawn around the data series at that point. If a moving average is being displayed, DateGraph will compute the standard deviation of the average at each point. (i.e. σ = sqrt((σ_1^2 + σ_2^2 + ... + σ_n^2)/n))
+ function annotationschange(el) {
+ if (el.checked) {
+ stockchart.setAnnotations(stock_annotations);
+ } else {
+ stockchart.setAnnotations([]);
+ }
+ }
+
+
+
+ Other Options
+
+ In addition to the options mentioned above (showRoller, rollPeriod, errorBars, valueRange), there are many others.
+
+ For a full list, see the Dygraphs Options Reference page.
+
+ Common Gotchas
+
+ Here are a few problems that I've frequently run into while using the dygraphs library.
+
+
+ - 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.
+ - 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 Firebug.
+ - Make sure your CSV files are in the correct format. They must be of the form
YYYYMMDD, series1, series2, … . And if you set the errorBars property, make sure you alternate data series and standard deviations.
+ - dygraphs are not happy when placed inside a
<center> tag. This applies to the CSS text-align property as well. If you want to center a Dygraph, put it inside a table with align = center set.
+ - Don't set the
dateWindow property to a date. It expects milliseconds since epoch, which can be obtained from a JavaScript Date object's valueOf method.
+ - 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.
+
+
+ GWT Compatibility
+ 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:
+
+
+<inherits name="org.danvk.dygraphs"/>
-
-
-
-
-
-Things to note here:
-
- - The errorBars option affects both the interpretation of the CSV file and the display of the graph. When errorBars is set to true, each line is interpreted as YYYYMMDD,A,sigma_A,B,sigma_B,...
- - The first line of the CSV file doesn't mention the error columns. In this case, it's just "Date,Series1,Series2".
- - 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.
- - The error bars are partially transparent. This can be seen when they overlap one another.
-
-
-One last demo
-
-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.
-
-
-
-
-
-Other Options
-These are the options that can be passed in through the fourth parameter of the DateGraph constructor.
-
-
- Name Sample Value Description
- rollPeriod
- 7Number of days over which to average data. Discussed extensively above.
-
- colors
- ['red', '#00FF00']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.
-
- colorSaturation
- 1.0If colors is not specified, saturation of the
- automatically-generated data series colors. (0.0-1.0, default:
- 1.0)
-
- colorValue
- 0.5If colors is not specified, value of the data series colors, as in
- hue/saturation/value. (0.0-1.0, default 0.5)
-
- clickCallback
- function(e,date){ alert(date); }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)
-
- errorBars
- falseDoes the data contain standard deviations? Setting this to true alters
- the input format (see above). (default false)
-
- strokeWidth
- 2.0Width of the data lines. This can be used to increase the contrast or
- some graphs. (default 1.0)
-
- dateWindow
- [(new Date('2006-01-01')).valueOf(),
- (new Date()).valueOf()]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.
-
- valueRange
- [10, 110]Explicitly set the vertical range of the graph to [low, high]. By
- default, some clever heuristics are used (see above).
-
- minTickSize
- 1
- 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.
-
- labelsSeparateLines
- truePut <br/> between lines in the label string. Often used in
- conjunction with labelsDiv. (default false)
-
- labelsDiv
- document.getElementById('foo')Show data labels in an external div, rather than on the graph. (default
- null)
-
- labelsKMB
- trueShow K/M/B for thousands/millions/billions on y-axis (default
- false).
-
-
- padding
- {left: 40, right: 30,
top: 5,
- bottom: 15}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.
-
-
-
-Any options you specify also get passed on to PlotKit's Renderer class. DateGraph will override some of these (e.g. strokeColor), but others may be useful. The padding property is an example of this.
-
-Common Gotchas
-Here are a few problems that I've frequently run into while using the
-dygraphs library.
-
-
- - 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 Firebug.
-
- - Make sure your CSV files are in the correct format. They must be of the
- form
YYYYMMDD,series1,series2,.... If you're specifying the
- names of each data series in the CSV file itself, make sure that you pass
- null as the third parameter to the DateGraph constructor to let
- the library know that. And if you set the errorBars property,
- make sure you alternate data series and standard deviations.
-
- - dygraphs are not happy when placed inside a
<center>
- tag. This applies to the CSS text-align property as well. If you
- want to center a DateGraph, put it inside a table with "align=center"
- set.
-
- - If you specify the
colors property or name the data series
- using the third parameter of the DateGraph constructor, make sure the number
- of data series agree in all places: colors, third parameter and
- in each line of the CSV file itself.
-
- - Don't set the
dateWindow property to a date. It expects
- milliseconds since epoch, which can be obtained from a JavaScript Date
- object's valueOf method.
-
-
-Created May 9, 2008 by Dan Vanderkam
+ return chart;
+}-*/;
+
+
+
+ Known Users
+ Since its public release in late 2009, dygraphs has found many users
+ across the web. This is a small collection of the uses that we know about.
+ If you're using dygraphs, please send Dan a link and he'll add it to this
+ list.
+
+ dygraphs was originally developed at Google and has found wide use on
+ internal dashboards and servers there. There are also a few uses of
+ dygraphs on public Google products:
+
+
+ - Google Correlate
+ Uses dygraphs for time series visualization. Mostly a standard configuration, with just a few tweaks to match Google style.
+
+ - Google Correlate - Search by Drawing
+ This is a highly customized configuration which lets the user draw a time series. Based on this demo.
+
+ - Google Latitude History Dashboard
+ Uses mouse interaction callbacks to synchronize time series points with markers on a Google Map.
+
+
+ dygraphs has also found use in other organizations:
+
+
+ - Integrated
+ Space Weather Analysis System (NASA)
+ “We use [dygraphs] in the Integrated Space Weather
+ Analysis System available from the Space Weather Laboratory at NASA Goddard
+ Space Flight Center. It works quite well for time series data from various
+ missions and simulations that we store.”
+
+
+ - Eutelsat
+ “Eutelsat uses dygraphs for charting spacecraft
+ telemetry for a fleet of 25 geostationary satellites. The spacecraft
+ engineers are very happy with it. All satellite combined are producing
+ about 200 millions unique data points per day so we really appreciate the
+ excellent performance of dygraphs.”
+
+ - 10gen MongoDB
+ Monitoring Service
+ A free monitoring service for MongoDB from 10gen (the
+ creators of MongoDB). Used by thousands of servers and users. Makes use of
+ synchronized charts to display many
+ quantities simultaneously.
+
+ - Duck Duck Go Traffic Dashboard
+ DDG uses dygraphs to display a public chart of their daily traffic. They use annotations and the moving average features.
+
+ - Wikimedia Foundation - Moodbar data dashboard
+ dygraphs is used internally at Wikimedia as a handy solution to monitor the
+ results of a bunch of small experiments.
+
+ - quadrant-framework (MySQL Load Testing Framework)
+ A user friendly framework for creating and visualizing
+ MySQL database load test jobs. For more information on its use of dygraphs,
+ see this post.
+
+ - Spinwave Systems (Home energy monitoring)
+ dygraphs is used to chart energy usage over time.
+
+
+ - Jwebchart
+
+ jWebChart is a stand-alone and Thredds' embedded plotting system for
+ netCDF files. NetCDF is a common standard for the storage and
+ distribution of scientific data.
+
+
+ - n-gramas - Explore las tendencias en los artÃculos periodÃsticos de Colombia.
+
+
+ (English: "Explore trends in newspaper articles of
+ Colombia"). dygraphs is used for displaying the results of this n-grams
+ viewer. Uses an extension for exporting the plots as PNG images
+ ([1], [2]).
+
+
+
+
+ Are you using dygraphs? Please let Dan know and he'll add your link here!
+
+
+ Data Policy
+ dygraphs is purely client-side JavaScript. It does not send your data to any servers – the data is processed entirely in the client's browser.
+
+ Created May 9, 2008 by Dan Vanderkam
+