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.
For the radar chart data, we have an array of datasets. Each of these is an object, with a fill colour, a stroke colour, a colour for the fill of each point, and a colour for the stroke of each point. We also have an array of data values.
The label key on each dataset is optional, and can be used when generating a scale for the chart.
### Chart options
These are the customisation options specific to Radar charts. These options are merged with the [global chart configuration options](#getting-started-global-chart-configuration), and form the options of the chart.
scale | Array | [See Scales](#scales) and [Defaults for Radial Linear Scale](#scales-radial-linear-scale) | Options for the one scale used on the chart. Use this to style the ticks, labels, and grid lines.
*scale*.type | String |"radialLinear" | As defined in ["Radial Linear"](#scales-radial-linear-scale).
*elements*.line | Array | | Options for all line elements used on the chart, as defined in the global elements, duplicated here to show Radar chart specific defaults.
We can also change these defaults values for each Radar type that is created, this object is available at `Chart.defaults.Radar`.
### Prototype methods
#### .getPointsAtEvent( event )
Calling `getPointsAtEvent(event)` on your Chart instance passing an argument of an event, or jQuery event, will return the point elements that are at that the same position of that event.
```javascript
canvas.onclick = function(evt){
var activePoints = myRadarChart.getPointsAtEvent(evt);
// => activePoints is an array of points on the canvas that are at the same position as the click event.
};
```
This functionality may be useful for implementing DOM based tooltips, or triggering custom behaviour in your application.
#### .update( )
Calling `update()` on your Chart instance will re-render the chart with any updated values, allowing you to edit the value of multiple existing points, then render those in one animated render loop.
```javascript
myRadarChart.datasets[0].points[2].value = 50;
// Would update the first dataset's value of 'Sleeping' to be 50
myRadarChart.update();
// Calling update now animates the position of Sleeping from 90 to 50.
```
#### .addData( valuesArray, label )
Calling `addData(valuesArray, label)` on your Chart instance passing an array of values for each dataset, along with a label for those points.
```javascript
// The values array passed into addData should be one for each dataset in the chart
myRadarChart.addData([40, 60], "Dancing");
// The new data will now animate at the end of the chart.
```
#### .removeData( )
Calling `removeData()` on your Chart instance will remove the first value for all datasets on the chart.
```javascript
myRadarChart.removeData();
// Other points will now animate to their correct positions.