Polar Scatter Chart

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

A polar scatter chart can be created as a polar line chart with data symbols. The line width is set to 0, so only the symbols can be seen. This will create the effects of a scatter chart.

The detail steps are:

Create a polar line layer using PolarChart.addLineLayer.
Enable data symbols for the line using PolarLayer.setDataSymbol (or PolarLayer.setDataSymbol2 or PolarLayer.setDataSymbol3 or PolarLayer.setDataSymbol4).
Disable the line by setting its width to 0 using PolarLayer.setLineWidth.

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

[JSP Version] jspdemo/polarscatter.jsp

<%@page import="ChartDirector.*, java.util.*" %>
<%
// The data for the chart
double[] data0 = {43, 89, 76, 64, 48, 18, 92, 68, 44, 79, 71, 85};
double[] angles0 = {45, 96, 169, 258, 15, 30, 330, 260, 60, 75, 110, 140};

double[] data1 = {50, 91, 26, 29, 80, 53, 62, 87, 19, 40};
double[] angles1 = {230, 210, 240, 310, 179, 250, 244, 199, 89, 160};

double[] data2 = {88, 65, 76, 49, 80, 53};
double[] angles2 = {340, 310, 340, 210, 30, 300};

// The labels on the angular axis (spokes)
String[] labels = {"North", "North\nEast", "East", "South\nEast", "South", "South\nWest", "West",
    "North\nWest"};

// 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*>Plants in Wonderland", "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 sector background color
c.setPlotAreaBg(0xdddddd, 0xeeeeee, false);

// 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, either 8 spokes
c.angularAxis().setLinearScale2(0, 360, labels);

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

// Add a blue (0xff) polar line layer to the chart using (data0, angle0)
PolarLineLayer layer0 = c.addLineLayer(data0, 0x0000ff, "Immortal Weed");
layer0.setAngles(angles0);

layer0.setLineWidth(0);
layer0.setDataSymbol(Chart.TriangleSymbol, 11);

// Add a red (0xff0000) polar line layer to the chart using (data1, angles1)
PolarLineLayer layer1 = c.addLineLayer(data1, 0xff0000, "Precious Flower");
layer1.setAngles(angles1);

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

// Use a 11 pixel diamond data point symbol
layer1.setDataSymbol(Chart.DiamondSymbol, 11);

// Add a green (0x00ff00) polar line layer to the chart using (data2, angles2)
PolarLineLayer layer2 = c.addLineLayer(data2, 0x00ff00, "Magical Tree");
layer2.setAngles(angles2);

// Disable the line by setting its width to 0, so only the symbols are visible
layer2.setLineWidth(0);

// Use a 9 pixel square data point symbol
layer2.setDataSymbol(Chart.SquareSymbol, 9);

// Output the chart
WebChartViewer viewer = new WebChartViewer(request, "chart1");
viewer.setChart(c, Chart.SVG);

// Include tool tip for the chart
viewer.setImageMap(c.getHTMLImageMap("", "", "title='{dataSetName} at ({value} km, {angle} deg)'"));
%>
<!DOCTYPE html>
<html>
<head>
    <title>Polar Scatter Chart</title>
    <!-- Include ChartDirector Javascript Library to support chart interactions -->
    <script type="text/javascript" src="cdjcv.js"></script>
</head>
<body style="margin:5px 0px 0px 5px">
    <div style="font:bold 18pt verdana;">
        Polar Scatter Chart
    </div>
    <hr style="border:solid 1px #000080; background:#000080" />
    <div style="font:10pt verdana; margin-bottom:1.5em">
        <a href="viewsource.jsp?file=<%=request.getServletPath()%>">View Source Code</a>
    </div>
    <!-- ****** Here is the chart image ****** -->
    <%= viewer.renderHTML(response) %>
</body>
</html>