Chart Scatter Bubble Series

ScatterBubbleSeries are a type of CartesianSeries that use Cartesian coordinates to display values for typically two variables for a set of data. The data are displayed as a collection of bubble, each having the value of one variable determining the position on the horizontal axis and the value of the other variable determining the position on the vertical axis. Unlike ScatterSeries they can visualize a third value (on top of the two value properties) through the size of the bubbles. If you want to show bubbles for categorical data, you can use BubbleSeries.

• Setup
• Bubble Scale
• References

Setup

To display a Scatter Bubble Chart, you will need to:

• Add a RadCartesianChart to your component.
• Add a category axis (CategoricalAxis, DateTimeCategoricalAxis or DateTimeContinuousAxis) with the v-tkCartesianHorizontalAxis directive.
• Add a value axis (LinearAxis or LogarithmicAxis) with the v-tkCartesianVerticalAxis directive.
• Add at least one instance of ScatterSeries with the v-tkCartesianSeries directive and set its items property to a collection of data items, the xProperty and yProperty to the names of the properties used to determine where to plot the scatter points and the bubbleSizeProperty to the name of the property used to determine the size of the bubble.

To illustrate this setup, let's create an example. Just like with all vue 'pages' let's start with the Component in which we will place our RadCartesianChart instance. Before that, we would create a basic JS or TS module that contains a collection of objects, which will be used by the chart to provide intuitive data visualization.

#### Example 1: Define a collection of items

export const getScatterData = () => {
  return new ObservableArray([
    { Age: 20, Salary: 10000, Spendings: 4500, Savings: 5500, Impact: 1 },
    { Age: 25, Salary: 12300, Spendings: 6500, Savings: 5200, Impact: 7 },
    { Age: 30, Salary: 14000, Spendings: 8500, Savings: 5500, Impact: 10 },
    { Age: 35, Salary: 18000, Spendings: 9500, Savings: 7500, Impact: 6 },
    { Age: 40, Salary: 19520, Spendings: 15540, Savings: 3800, Impact: 4 },
    { Age: 45, Salary: 20000, Spendings: 15500, Savings: 4500, Impact: 2 },
    { Age: 50, Salary: 24200, Spendings: 20500, Savings: 3700, Impact: 11 },
    { Age: 55, Salary: 24000, Spendings: 22500, Savings: 1500, Impact: 8 },
    { Age: 60, Salary: 22000, Spendings: 22500, Savings: 500, Impact: 1 },
    { Age: 65, Salary: 20000, Spendings: 20500, Savings: 10, Impact: 9 }
  ]);
};

#### Example 2: Add chart to component's template

import { getScatterData } from '../../data';

const description = 'Scatter Bubble Series';

export default {
  name: 'ScatterBubbleSeriesExample',
  description: description,
  template: `
  <Page>
    <ActionBar :title="title">
      <NavigationButton text="Back" android.systemIcon="ic_menu_back" @tap="onNavigationButtonTap"></NavigationButton>
    </ActionBar>
    <RadCartesianChart>
      <LinearAxis v-tkCartesianHorizontalAxis></LinearAxis>
      <LinearAxis v-tkCartesianVerticalAxis></LinearAxis>

      <ScatterBubbleSeries v-tkCartesianSeries :items="items" bubbleScale="5" xProperty="Age" yProperty="Salary" bubbleSizeProperty="Impact"></ScatterBubbleSeries>
      <ScatterBubbleSeries v-tkCartesianSeries :items="items" bubbleScale="5" xProperty="Age" yProperty="Spendings" bubbleSizeProperty="Impact"></ScatterBubbleSeries>
      <ScatterBubbleSeries v-tkCartesianSeries :items="items" bubbleScale="5" xProperty="Age" yProperty="Savings" bubbleSizeProperty="Impact"></ScatterBubbleSeries>
    </RadCartesianChart>
  </Page>
  `,
  data () {
    return {
      title: description,
      items: getScatterData(),
    };
  },
  methods: {
    onNavigationButtonTap() {
      Frame.topmost().goBack();
    },
  },
};

Figure 1: Chart with ScatterBubbleSeries on Android (left) and iOS (right)

Bubble Scale

Additionally, ScatterBubbleSeries expose a bubbleScale property which can be used to fine-tune the size of the bubbles according to specific application requirements. The way the bubbleScale property works is by multiplying its value to the radius calculated for each data-point's bubble to determine the bubble's final size.

References

Want to see this scenario in action? Check our SDK examples repo on GitHub. You will find this and many other practical examples with NativeScript UI.

Examples used in this article:

• Scatter Bubble Series Example

Related articles you might find useful:

• Bubble Series
• Range Bar Series
• Scatter Series