Sankey Charts with Multiple levels

Following is an example of a SanKey Chart with multiple levels.

We have already seen the configurations used to draw a chart in Google Charts Configuration Syntax chapter. Now, let us see an example of a SanKey Chart with multiple levels.

Configurations

We've used Sankey class to show a Sankey chart with multiple levels.

Sankey chart = new Sankey();

Example

HelloWorld.java

package com.tutorialspoint.client;

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.client.ui.RootPanel;

import com.googlecode.gwt.charts.client.ChartLoader;
import com.googlecode.gwt.charts.client.ChartPackage;
import com.googlecode.gwt.charts.client.ColumnType;
import com.googlecode.gwt.charts.client.DataTable;
import com.googlecode.gwt.charts.client.sankey.Sankey;

public class HelloWorld implements EntryPoint {
   private Sankey chart;

   private void initialize() {
      ChartLoader chartLoader = new ChartLoader(ChartPackage.SANKEY);
      chartLoader.loadApi(new Runnable() {
         public void run() {
            // Create and attach the chart
            chart = new Sankey();
            RootPanel.get().add(chart);
            draw();
         }
      });
   }
   private void draw() {
      // Prepare the data
      DataTable data = DataTable.create();
      data.addColumn(ColumnType.STRING, "From");
      data.addColumn(ColumnType.STRING, "To");
      data.addColumn(ColumnType.NUMBER, "Weight");

      data.addRow("Brazil","Portugal",5);
      data.addRow("Brazil","France",1 );
      data.addRow("Brazil","Spain",1 );
      data.addRow("Brazil","England",1 );
      data.addRow("Canada","Portugal",1 );
      data.addRow("Canada","France",5 );
      data.addRow("Canada","England",1 );
      data.addRow("Mexico","Portugal",1 );
      data.addRow("Mexico","France",1 );
      data.addRow("Mexico","Spain",5 );
      data.addRow("Mexico","England",1 );
      data.addRow("USA","Portugal",1 );
      data.addRow("USA","France",1 );
      data.addRow("USA","Spain",1 );
      data.addRow("USA","England",5);     
      data.addRow("Portugal","Angola", 2 );
      data.addRow("Portugal","Senegal", 1 );
      data.addRow("Portugal", "Morocco", 1 );
      data.addRow("Portugal","South Africa", 3 );

      // Draw the chart
      chart.draw(data);
      chart.setWidth("400px");
      chart.setHeight("400px");
   }
   public void onModuleLoad() {
      initialize();
   }
}

Result

Verify the result.