ChartDirector 6.1 (Java Edition)

Polar Bubble Chart




This example demonstrates how to create polar bubble charts. It also demonstrates using alternating background colors along the radial direction.

A polar bubble chart can be created as a polar line chart with circles as data symbols. The line width is set to 0, so only the symbols can be seen. The symbol sizes are then controlled using another data series. This will create the effects of a bubble chart.

The detail steps are:

Note that in this example, the polar plot area uses two alternating background colors along the radial direction. This is by using PolarChart.setPlotAreaBg.

Source Code Listing

[JSP Version] jspdemo/polarbubble.jsp
<%@page import="ChartDirector.*" %>
<%
// The data for the chart
double[] data0 = {6, 12.5, 18.2, 15};
double[] angles0 = {45, 96, 169, 258};
double[] size0 = {41, 105, 12, 20};

double[] data1 = {18, 16, 11, 14};
double[] angles1 = {30, 210, 240, 310};
double[] size1 = {30, 45, 12, 90};

// Create a PolarChart object of size 460 x 460 pixels
PolarChart c = new PolarChart(460, 460);

// Add a title to the chart at the top left corner using 15pt Arial Bold Italic font
c.addTitle2(Chart.TopLeft, "<*underline=2*>EM Field Strength", "Arial Bold Italic", 15);

// Set center of plot area at (230, 240) with radius 180 pixels
c.setPlotArea(230, 240, 180);

// Use alternative light grey/dark grey circular background color
c.setPlotAreaBg(0xdddddd, 0xeeeeee);

// Set the grid style to circular grid
c.setGridStyle(false);

// Add a legend box at the top right corner of the chart using 9pt Arial Bold font
c.addLegend(459, 0, true, "Arial Bold", 9).setAlignment(Chart.TopRight);

// Set angular axis as 0 - 360, with a spoke every 30 units
c.angularAxis().setLinearScale(0, 360, 30);

// Set the radial axis label format
c.radialAxis().setLabelFormat("{value} km");

// Add a blue (0x9999ff) line layer to the chart using (data0, angle0)
PolarLineLayer layer0 = c.addLineLayer(data0, 0x9999ff, "Cold Spot");
layer0.setAngles(angles0);

// Disable the line by setting its width to 0, so only the symbols are visible
layer0.setLineWidth(0);

// Use a circular data point symbol
layer0.setDataSymbol(Chart.CircleSymbol, 11);

// Modulate the symbol size by size0 to produce a bubble chart effect
layer0.setSymbolScale(size0);

// Add a red (0xff9999) line layer to the chart using (data1, angle1)
PolarLineLayer layer1 = c.addLineLayer(data1, 0xff9999, "Hot Spot");
layer1.setAngles(angles1);

// Disable the line by setting its width to 0, so only the symbols are visible
layer1.setLineWidth(0);

// Use a circular data point symbol
layer1.setDataSymbol(Chart.CircleSymbol, 11);

// Modulate the symbol size by size1 to produce a bubble chart effect
layer1.setSymbolScale(size1);

// Output the chart
String chart1URL = c.makeSession(request, "chart1");

// Include tool tip for the chart
String imageMap1 = c.getHTMLImageMap("", "",
    "title='{dataSetName} at ({value} km, {angle} deg)\nStrength = {z} Watt'");
%>
<html>
<body style="margin:5px 0px 0px 5px">
<div style="font-size:18pt; font-family:verdana; font-weight:bold">
    Polar Bubble Chart
</div>
<hr color="#000080">
<div style="font-size:10pt; font-family:verdana; margin-bottom:1.5em">
    <a href="viewsource.jsp?file=<%=request.getServletPath()%>">View Source Code</a>
</div>
<img src='<%=response.encodeURL("getchart.jsp?"+chart1URL)%>'
    usemap="#map1" border="0">
<map name="map1"><%=imageMap1%></map>
</body>
</html>

[Java Version] javademo/polarbubble.java
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import ChartDirector.*;

public class polarbubble implements DemoModule
{
    //Name of demo program
    public String toString() { return "Polar Bubble Chart"; }

    //Number of charts produced in this demo
    public int getNoOfCharts() { return 1; }

    //Main code for creating charts
    public void createChart(ChartViewer viewer, int chartIndex)
    {
        // The data for the chart
        double[] data0 = {6, 12.5, 18.2, 15};
        double[] angles0 = {45, 96, 169, 258};
        double[] size0 = {41, 105, 12, 20};

        double[] data1 = {18, 16, 11, 14};
        double[] angles1 = {30, 210, 240, 310};
        double[] size1 = {30, 45, 12, 90};

        // Create a PolarChart object of size 460 x 460 pixels
        PolarChart c = new PolarChart(460, 460);

        // Add a title to the chart at the top left corner using 15pt Arial Bold Italic font
        c.addTitle2(Chart.TopLeft, "<*underline=2*>EM Field Strength", "Arial Bold Italic", 15);

        // Set center of plot area at (230, 240) with radius 180 pixels
        c.setPlotArea(230, 240, 180);

        // Use alternative light grey/dark grey circular background color
        c.setPlotAreaBg(0xdddddd, 0xeeeeee);

        // Set the grid style to circular grid
        c.setGridStyle(false);

        // Add a legend box at the top right corner of the chart using 9pt Arial Bold font
        c.addLegend(459, 0, true, "Arial Bold", 9).setAlignment(Chart.TopRight);

        // Set angular axis as 0 - 360, with a spoke every 30 units
        c.angularAxis().setLinearScale(0, 360, 30);

        // Set the radial axis label format
        c.radialAxis().setLabelFormat("{value} km");

        // Add a blue (0x9999ff) line layer to the chart using (data0, angle0)
        PolarLineLayer layer0 = c.addLineLayer(data0, 0x9999ff, "Cold Spot");
        layer0.setAngles(angles0);

        // Disable the line by setting its width to 0, so only the symbols are visible
        layer0.setLineWidth(0);

        // Use a circular data point symbol
        layer0.setDataSymbol(Chart.CircleSymbol, 11);

        // Modulate the symbol size by size0 to produce a bubble chart effect
        layer0.setSymbolScale(size0);

        // Add a red (0xff9999) line layer to the chart using (data1, angle1)
        PolarLineLayer layer1 = c.addLineLayer(data1, 0xff9999, "Hot Spot");
        layer1.setAngles(angles1);

        // Disable the line by setting its width to 0, so only the symbols are visible
        layer1.setLineWidth(0);

        // Use a circular data point symbol
        layer1.setDataSymbol(Chart.CircleSymbol, 11);

        // Modulate the symbol size by size1 to produce a bubble chart effect
        layer1.setSymbolScale(size1);

        // Output the chart
        viewer.setChart(c);

        //include tool tip for the chart
        viewer.setImageMap(c.getHTMLImageMap("clickable", "",
            "title='{dataSetName} at ({value} km, {angle} deg) Strength = {z} Watt'"));
    }

    //Allow this module to run as standalone program for easy testing
    public static void main(String[] args)
    {
        //Instantiate an instance of this demo module
        DemoModule demo = new polarbubble();

        //Create and set up the main window
        JFrame frame = new JFrame(demo.toString());
        frame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {System.exit(0);} });
        frame.getContentPane().setBackground(Color.white);

        // Create the chart and put them in the content pane
        ChartViewer viewer = new ChartViewer();
        demo.createChart(viewer, 0);
        frame.getContentPane().add(viewer);

        // Display the window
        frame.pack();
        frame.setVisible(true);
    }
}