Simple Radar Chart

This example demonstrates the basic steps in creating radar charts.

Create a PolarChart object using PolarChart.PolarChart.
Specify the polar plot area of the chart using PolarChart.setPlotArea.
Add a polar area layer and specify the data for the area using PolarChart.addAreaLayer.
Specify the labels on the angular axis using AngularAxis.setLabels. In a polar/radar chart, the radial axis refers to the axis from the center to the perimeter of the plot area, and the angular axis refers to the axis lying on the perimeter of the plot area.
Generate the chart using BaseChart.makeChart2.

[Ruby On Rails Version - Controller] app/controllers/simpleradar_controller.rb

require("chartdirector")

class SimpleradarController < ApplicationController

    def index()
        @title = "Simple Radar Chart"
        @ctrl_file = File.expand_path(__FILE__)
        @noOfCharts = 1
        render :template => "templates/chartview"
    end

    #
    # Render and deliver the chart
    #
    def getchart()
        # The data for the chart
        data = [90, 60, 65, 75, 40]

        # The labels for the chart
        labels = ["Speed", "Reliability", "Comfort", "Safety", "Efficiency"]

        # Create a PolarChart object of size 450 x 350 pixels
        c = ChartDirector::PolarChart.new(450, 350)

        # Set center of plot area at (225, 185) with radius 150 pixels
        c.setPlotArea(225, 185, 150)

        # Add an area layer to the polar chart
        c.addAreaLayer(data, 0x9999ff)

        # Set the labels to the angular axis as spokes
        c.angularAxis().setLabels(labels)

        # Output the chart
        send_data(c.makeChart2(ChartDirector::PNG), :type => "image/png", :disposition => "inline")

    end

end

[Ruby On Rails Version - View] app/views/templates/chartview.html.erb

<html>
<body style="margin:5px 0px 0px 5px">

<!-- Title -->
<div style="font-size:18pt; font-family:verdana; font-weight:bold">
    <%= @title %>
</div>
<hr style="border:solid 1px #000080" />

<!-- Source Code Listing Link -->
<div style="font-size:9pt; font-family:verdana; margin-bottom:1.5em">
    <%= link_to "Source Code Listing", 
        :controller => "cddemo", :action => "viewsource",
        :ctrl_file => @ctrl_file, :view_file => File.expand_path(__FILE__) %>
</div>

<!-- Create one or more IMG tags to display the demo chart(s) -->
<% 0.upto(@noOfCharts - 1) do |i| %>
    <img src="<%= url_for(:action => "getchart", :img => i) %>">
<% end %>

</body>
</html>

[Command Line Version] rubydemo/simpleradar.rb

#!/usr/bin/env ruby
require("chartdirector")

# The data for the chart
data = [90, 60, 65, 75, 40]

# The labels for the chart
labels = ["Speed", "Reliability", "Comfort", "Safety", "Efficiency"]

# Create a PolarChart object of size 450 x 350 pixels
c = ChartDirector::PolarChart.new(450, 350)

# Set center of plot area at (225, 185) with radius 150 pixels
c.setPlotArea(225, 185, 150)

# Add an area layer to the polar chart
c.addAreaLayer(data, 0x9999ff)

# Set the labels to the angular axis as spokes
c.angularAxis().setLabels(labels)

# Output the chart
c.makeChart("simpleradar.png")