radar.md

Radar

A radar chart is a way of showing multiple data points and the variation between them.

They are often useful for comparing the points of two or more different data sets.

{% chartjs %} { "type": "radar", "data": { "labels": [ "Eating", "Drinking", "Sleeping", "Designing", "Coding", "Cycling", "Running" ], "datasets": [{ "label": "My First Dataset", "data": [65, 59, 90, 81, 56, 55, 40], "fill": true, "backgroundColor": "rgba(255, 99, 132, 0.2)", "borderColor": "rgb(255, 99, 132)", "pointBackgroundColor": "rgb(255, 99, 132)", "pointBorderColor": "#fff", "pointHoverBackgroundColor": "#fff", "pointHoverBorderColor": "rgb(255, 99, 132)", "fill": true }, { "label": "My Second Dataset", "data": [28, 48, 40, 19, 96, 27, 100], "fill": true, "backgroundColor": "rgba(54, 162, 235, 0.2)", "borderColor": "rgb(54, 162, 235)", "pointBackgroundColor": "rgb(54, 162, 235)", "pointBorderColor": "#fff", "pointHoverBackgroundColor": "#fff", "pointHoverBorderColor": "rgb(54, 162, 235)", "fill": true }] }, "options": { "elements": { "line": { "tension": 0, "borderWidth": 3 } } } } {% endchartjs %}

Example Usage

var myRadarChart = new Chart(ctx, {
    type: 'radar',
    data: data,
    options: options
});

Dataset Properties

The radar chart allows a number of properties to be specified for each dataset. These are used to set display properties for a specific dataset. For example, the colour of a line is generally set this way.

Name	Type	Scriptable	Indexable	Default
backgroundColor	Color	Yes	-	'rgba(0, 0, 0, 0.1)'
borderCapStyle	string	Yes	-	'butt'
borderColor	Color	Yes	-	'rgba(0, 0, 0, 0.1)'
borderDash	number[]	Yes	-	[]
borderDashOffset	number	Yes	-	0.0
borderJoinStyle	string	Yes	-	'miter'
borderWidth	number	Yes	-	3
fill	boolean|string	Yes	-	true
label	string	-	-	''
lineTension	number	-	-	0
pointBackgroundColor	Color	Yes	Yes	'rgba(0, 0, 0, 0.1)'
pointBorderColor	Color	Yes	Yes	'rgba(0, 0, 0, 0.1)'
pointBorderWidth	number	Yes	Yes	1
pointHitRadius	number	Yes	Yes	1
pointHoverBackgroundColor	Color	Yes	Yes	undefined
pointHoverBorderColor	Color	Yes	Yes	undefined
pointHoverBorderWidth	number	Yes	Yes	1
pointHoverRadius	number	Yes	Yes	4
pointRadius	number	Yes	Yes	3
pointRotation	number	Yes	Yes	0
pointStyle	string|Image	Yes	Yes	'circle'
spanGaps	boolean	-	-	undefined

General

Name	Description
label	The label for the dataset which appears in the legend and tooltips.

Point Styling

The style of each point can be controlled with the following properties:

Name	Description
pointBackgroundColor	The fill color for points.
pointBorderColor	The border color for points.
pointBorderWidth	The width of the point border in pixels.
pointHitRadius	The pixel size of the non-displayed point that reacts to mouse events.
pointRadius	The radius of the point shape. If set to 0, the point is not rendered.
pointRotation	The rotation of the point in degrees.
pointStyle	Style of the point. more...

All these values, if undefined, fallback first to the dataset options then to the associated elements.point.* options.

Line Styling

The style of the line can be controlled with the following properties:

Name	Description
backgroundColor	The line fill color.
borderCapStyle	Cap style of the line. See MDN.
borderColor	The line color.
borderDash	Length and spacing of dashes. See MDN.
borderDashOffset	Offset for line dashes. See MDN.
borderJoinStyle	Line joint style. See MDN.
borderWidth	The line width (in pixels).
fill	How to fill the area under the line. See area charts.
lineTension	Bezier curve tension of the line. Set to 0 to draw straightlines.
spanGaps	If true, lines will be drawn between points with no or null data. If false, points with NaN data will create a break in the line.

If the value is undefined, spanGaps fallback to the associated chart configuration options. The rest of the values fallback to the associated elements.line.* options.

Interactions

The interaction with each point can be controlled with the following properties:

Name	Description
pointHoverBackgroundColor	Point background color when hovered.
pointHoverBorderColor	Point border color when hovered.
pointHoverBorderWidth	Border width of point when hovered.
pointHoverRadius	The radius of the point when hovered.

Configuration Options

The radar chart defines the following configuration options. These options are merged with the global chart configuration options, Chart.defaults.global, to form the options passed to the chart.

Name	Type	Default	Description
spanGaps	boolean	false	If false, NaN data causes a break in the line.

Scale Options

The radar chart supports only a single scale. The options for this scale are defined in the scale property. The options for this scale are defined in the scale property, which can be referenced from the Linear Radial Axis page.

options = {
    scale: {
        angleLines: {
            display: false
        },
        ticks: {
            suggestedMin: 50,
            suggestedMax: 100
        }
    }
};

Default Options

It is common to want to apply a configuration setting to all created radar charts. The global radar chart settings are stored in Chart.defaults.radar. Changing the global options only affects charts created after the change. Existing charts are not changed.

Data Structure

The data property of a dataset for a radar chart is specified as an array of numbers. Each point in the data array corresponds to the label at the same index.

data: [20, 10]

For a radar chart, to provide context of what each point means, we include an array of strings that show around each point in the chart.

data: {
    labels: ['Running', 'Swimming', 'Eating', 'Cycling'],
    datasets: [{
        data: [20, 10, 4, 2]
    }]
}