dygraphs JavaScript Visualization Library

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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.

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A demo is worth a thousand words:

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(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.)

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Temperatures in New York vs. San Francisco

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Some things to notice:

There's less seasonal temperature variation in SF than in NY.
The difference is about 15° F for SF vs. 50° F for NY.
The daily data (set rolling period to 1) is quite noisy and hides this conclusion.
Using a 14-day moving average makes it clearer. A 100-day rolling period averages out nearly all the specifics from the data.
There's a gap in the data for SF, when the weather station was down (zoom into October 2007 to see it).
The bands around each point indicate average highs and lows.
There is a lot of data in this chart: low, average and high for each city on each day of a three year period ≈ 6000 data points in all.

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dygraphs allows the user to explore the data and discover these facts.

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For more demos, browse the dygraph tests directory.

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+ …makes this chart! +

The chart is interactive: you can mouse over to highlight individual values. You can click and drag to zoom. Double-clicking will zoom you back out. Shift-drag will pan. You can change the number and hit enter to adjust the averaging period.

Name	Values	Default	Description
includeZero	`boolean`	`false`	Usually, dygraphs will use the range of the data plus some padding to set the range of the y-axis. If this option is set, the y-axis will always include zero, typically as the lowest value. This can be used to avoid exaggerating the variance in the data.
rollPeriod	`integer >= 1`	`1`	Number of days over which to average data. Discussed extensively above.
showRoller	`boolean`	`false`	If the rolling average period text box should be shown.
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	`0.0 - 1.0`	`1.0`	If colors is not specified, saturation of the automatically-generated data series colors.
colorValue	`float (0.0 — 1.0)`	`1.0`	If 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); }`	`null`	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)
zoomCallback	`function(minDate, maxDate){}`	`null`	A function to call when the zoom window is changed (either by zooming in or out). minDate and maxDate are milliseconds since epoch.
strokeWidth	`integer`	`1`	Width of the data lines. This can be used to increase the contrast or some graphs.
dateWindow	`[ Date.parse('2006-01-01'), (new Date()).valueOf() ]`	`Full range of the input is shown`	Initially zoom in on a section of the graph. Is of the form [earliest, latest], where earliest/latest are milliseconds since epoch.
valueRange	`[10, 110]`	`Full range of the input is shown`	Explicitly set the vertical range of the graph to [low, high].
labelsSeparateLines	`boolean`	`false`	Put `<br/>` between lines in the label string. Often used in conjunction with labelsDiv.
labelsDiv	`document.getElementById('foo')`	`null`	Show data labels in an external div, rather than on the graph.
labelsKMB	`true`	`false`	Show K/M/B for thousands/millions/billions on y-axis.
labelsKMG2	`true`	`false`	Show k/M/G for kilo/Mega/Giga on y-axis. This is different than - `labelsKMB` in that it uses base 2, not 10.
labelsDivWidth	`250`		Width (in pixels) of the div which shows information on the currently-highlighted points.
labelsDivStyles	`{}`	`null`	Additional styles to apply to the currently-highlighted points div. For example, { 'font-weight': 'bold' } will make the labels bold.
highlightCircleSize	`integer`	`3`	The size in pixels of the dot drawn over highlighted points.
drawPoints	`boolean`	`false`	Draw a small dot at each point, in addition to a line going through the point. This makes the individual data points easier to see, but can increase visual clutter in the chart.
pointSize	`interger`	`1`	The size of the dot to draw on each point in pixels (see drawPoints). A dot is always drawn when a point is "isolated", i.e. there is a missing point on either side of it. This also controls the size of those dots.
pixelsPerXLabel	`integer`	`60`	Number of pixels to require between each x- and y-label. Larger values will yield a sparser axis with fewer ticks.
pixelsPerYLabel	`integer`	`30`
xAxisLabelWidth	`integer`		Width (in pixels) of the x- and y-axis labels.
yAxisLabelWidth	`integer`		Width (in pixels) of the x- and y-axis labels.
axisLabelFontSize	`integer`	`14`	Size of the font (in pixels) to use in the axis labels, both x- and y-axis.
rightGap	`integer`		Number of pixels to leave blank at the right edge of the Dygraph. This makes it easier to highlight the right-most data point.
errorBars	`boolean`	`false`	Does the data contain standard deviations? Setting this to true alters the input format (see above).
sigma	`integer`		When errorBars is set, shade this many standard deviations above/below each point.
fractions	`boolean`	`false`	When set, attempt to parse each cell in the CSV file as "a/b", where a and b are integers. The ratio will be plotted. This allows computation of Wilson confidence intervals (see below).
wilsonInterval	`boolean`	`true`	Use in conjunction with the "fractions" option. Instead of plotting +/- N standard deviations, dygraphs will compute a Wilson confidence interval and plot that. This has more reasonable behavior for ratios close to 0 or 1.
customBars	`boolean`	`false`	When set, parse each CSV cell as "low;middle;high". Error bars will be drawn for each point between low and high, with the series itself going through middle.

Documentation

Project

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dygraphs is a fast, flexible open source JavaScript charting library.

dygraphs JavaScript Visualization Library

A demo is worth a thousand words:

Some things to notice:

Features

Usage

HTML

OUTPUT

HTML

OUTPUT

HTML

OUTPUT

Error Bars

Getting Started

HTML

OUTPUT

Quick Links

Internet Explorer Compatibility

GViz Data

Charting Fractions

One last demo

Other Options

Common Gotchas

Data Policy