JavaFX - Scatter Chart

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A scatterplot is a type of graph which uses values from two variables plotted in a Cartesian plane. It is usually used to find out the relationship between two variables.

Following is a Scatter chart plotted between area and weight.

Scatter Chart in JavaFX

In JavaFX, a Scatter chart is represented by a class named ScatterChart. This class belongs to the package javafx.scene.chart. By instantiating this class, you can create a ScatterChart node in JavaFX.

To generate an area chart in JavaFX, follow the steps given below.

Step 1: Defining the Axis

Define the X and Y axis of the area chart and set labels to them in start() method of Application class. In our example, X axis represents area and the Y axis represents weights.

public class ClassName extends Application {  
   @Override     
   public void start(Stage primaryStage) throws Exception {
      //Defining the x axis               
      NumberAxis xAxis = new NumberAxis(0, 12, 3); 
      xAxis.setLabel("Area");          
        
      //Defining the y axis 
      NumberAxis yAxis = new NumberAxis(0, 16, 4); 
      yAxis.setLabel("Weight");
   }    
}

Step 2: Creating the Scatter Chart

Create a line chart by instantiating the class named ScatterChart of the package javafx.scene.chart. To the constructor of this class, pass the objects representing the X and Y axis created in the previous step.

//Creating the Scatter chart 
ScatterChart<String, Number> scatterChart = new ScatterChart(xAxis, yAxis); 

Step 3: Preparing the Data

Instantiate the XYChart.Series class and add the data (a series of, x and y coordinates) to the Observable list of this class as follows −

//Prepare XYChart.Series objects by setting data 
XYChart.Series series = new XYChart.Series();  
series.getData().add(new XYChart.Data(8, 12)); 
series.getData().add(new XYChart.Data(4, 5.5)); 
series.getData().add(new XYChart.Data(11, 14)); 
series.getData().add(new XYChart.Data(4, 5)); 
series.getData().add(new XYChart.Data(3, 3.5)); 
series.getData().add(new XYChart.Data(6.5, 7)); 

Step 4: Add Data to the Scatter Chart

Add the data series prepared in the previous step to the scatter chart as follows −

//Setting the data to scatter chart        
scatterChart.getData().addAll(series);

Step 5: Creating a Group Object

In the start() method, create a group object by instantiating the class named Group. This belongs to the package javafx.scene.

Pass the ScatterChart (node) object created in the previous step as a parameter to the constructor of the Group class. This should be done in order to add it to the group as follows −

Group root = new Group(scatterChart);

Step 6: Launching Application

Lastly, follow the given steps below to launch the application properly −

• Firstly, instantiate the class named Scene by passing the Group object as a parameter value to its constructor. To this constructor, you can also pass dimensions of the application screen as optional parameters.

• Then, set the title to the stage using the setTitle() method of the Stage class.

• Now, a Scene object is added to the stage using the setScene() method of the class named Stage.

• Display the contents of the scene using the method named show().

• Lastly, the application is launched with the help of the launch() method.

Example

The following table contains sample data plotted between area and weight.

Following is a Java program which generates a scatter chart depicting the above data using JavaFX.

Save this code in a file with the name ScatterChartExample.java.

import javafx.application.Application; 
import static javafx.application.Application.launch; 
import javafx.scene.Group; 
import javafx.scene.Scene; 
import javafx.stage.Stage; 
import javafx.scene.chart.NumberAxis; 
import javafx.scene.chart.ScatterChart; 
import javafx.scene.chart.XYChart; 
         
public class ScatterChartExample extends Application { 
   @Override 
   public void start(Stage stage) {     
      //Defining the axes               
      NumberAxis xAxis = new NumberAxis(0, 12, 3); 
      xAxis.setLabel("Area");          
        
      NumberAxis yAxis = new NumberAxis(0, 16, 4); 
      yAxis.setLabel("Weight"); 
      
      //Creating the Scatter chart 
      ScatterChart<String, Number> scatterChart = 
      new ScatterChart(xAxis, yAxis);         
         
      //Prepare XYChart.Series objects by setting data 
      XYChart.Series series = new XYChart.Series();  
      series.getData().add(new XYChart.Data(8, 12)); 
      series.getData().add(new XYChart.Data(4, 5.5)); 
      series.getData().add(new XYChart.Data(11, 14)); 
      series.getData().add(new XYChart.Data(4, 5)); 
      series.getData().add(new XYChart.Data(3, 3.5)); 
      series.getData().add(new XYChart.Data(6.5, 7));  
                
      //Setting the data to scatter chart        
      scatterChart.getData().addAll(series); 
         
      //Creating a Group object  
      Group root = new Group(scatterChart); 
         
      //Creating a scene object 
      Scene scene = new Scene(root, 600, 400);  
      
      //Setting title to the Stage 
      stage.setTitle("Scatter Chart"); 
         
      //Adding scene to the stage 
      stage.setScene(scene); 
         
      //Displaying the contents of the stage 
      stage.show(); 
   } 
   public static void main(String args[]){ 
      launch(args); 
   } 
}

Compile and execute the saved java file from the command prompt using the following commands.

javac --module-path %PATH_TO_FX% --add-modules javafx.controls ScatterChartExample.java 
java --module-path %PATH_TO_FX% --add-modules javafx.controls ScatterChartExample

Output

On executing, the above program generates a JavaFX window displaying a scatter chart as shown below.

Example

The following table illustrates the number of electronic items that were in sold per month.

Following is a Java program which generates a scatter chart depicting the above data using JavaFX.

Save this code in a file with the name ScatterChartSales.java.

import javafx.application.Application; 
import static javafx.application.Application.launch; 
import javafx.scene.Group; 
import javafx.scene.Scene; 
import javafx.stage.Stage; 
import javafx.scene.chart.NumberAxis; 
import javafx.scene.chart.CategoryAxis;
import javafx.scene.chart.ScatterChart; 
import javafx.scene.chart.XYChart; 
         
public class ScatterChartExample extends Application { 
   @Override 
   public void start(Stage stage) {     
      //Defining the axes               
      CategoryAxis xAxis = new CategoryAxis(); 
      xAxis.setLabel("Items");          
        
      NumberAxis yAxis = new NumberAxis(); 
      yAxis.setLabel("Sales (per month)"); 
      
      //Creating the Scatter chart 
      ScatterChart scatterChart = 
      new ScatterChart(xAxis, yAxis);         
         
      //Prepare XYChart.Series objects by setting data 
      XYChart.Series series = new XYChart.Series(); 
      series.setName("Items sold per month"); 
        
      series.getData().add(new XYChart.Data("Laptop", 176)); 
      series.getData().add(new XYChart.Data("TV", 30)); 
      series.getData().add(new XYChart.Data("Mobile", 540)); 
      series.getData().add(new XYChart.Data("Smart Watch", 250)); 
      series.getData().add(new XYChart.Data("MacBook", 60));  
                
      //Setting the data to scatter chart        
      scatterChart.getData().addAll(series); 
         
      //Creating a Group object  
      Group root = new Group(scatterChart); 
         
      //Creating a scene object 
      Scene scene = new Scene(root, 600, 400);  
      
      //Setting title to the Stage 
      stage.setTitle("Scatter Chart"); 
         
      //Adding scene to the stage 
      stage.setScene(scene); 
         
      //Displaying the contents of the stage 
      stage.show(); 
   } 
   public static void main(String args[]){ 
      launch(args); 
   } 
}

Compile and execute the saved java file from the command prompt using the following commands.

javac --module-path %PATH_TO_FX% --add-modules javafx.controls ScatterChartSales.java 
java --module-path %PATH_TO_FX% --add-modules javafx.controls ScatterChartSales

Output

On executing, the above program generates a JavaFX window displaying a scatter chart as shown below.