Simple Rose Chart

This example demonstrates how to create a rose chart.

A rose chart is basically a polar chart with sectors of variable radius. This can be achieved by creating a PolarChart object as the graph paper, and adding sector zones on it using AngularAxis.addZone.

To enable auto-scale of the axis, in this example, we also add the radius data to a transparent line layer using PolarChart.addLineLayer. The line layer has no visible effect, but it causes the radial axis to auto-scale so that it covers the radius data.

[File: phpdemo/rose.php]

<?php
require_once("../lib/phpchartdir.php");

# Data for the chart
$data = array(9.4, 1.8, 2.1, 2.3, 3.5, 7.7, 8.8, 6.1, 5.0, 3.1, 6.0, 4.3, 5.1, 2.6,
    1.5, 2.2, 5.1, 4.3, 4.0, 9.0, 1.7, 8.8, 9.9, 9.5);
$angles = array(0, 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 165, 180, 195, 210,
    225, 240, 255, 270, 285, 300, 315, 330, 345);

# Create a PolarChart object of size 460 x 460 pixels, with a silver background and a
# 1 pixel 3D border
$c = new PolarChart(460, 460, silverColor(), 0x000000, 1);

# Add a title to the chart at the top left corner using 15pts Arial Bold Italic font.
# Use white text on deep blue background.
$textBoxObj = $c->addTitle("Polar Vector Chart Demonstration", "arialbi.ttf", 15,
    0xffffff);
$textBoxObj->setBackground(0x000080);

# Set plot area center at (230, 240) with radius 180 pixels and white background
$c->setPlotArea(230, 240, 180, 0xffffff);

# Set the grid style to circular grid
$c->setGridStyle(false);

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

# Add sectors to the chart as sector zones
for($i = 0; $i < count($data); ++$i) {
    $c->angularAxis->addZone($angles[$i], $angles[$i] + 15, 0, $data[$i], 0x33ff33,
        0x008000);
}

# Add an Transparent invisible layer to ensure the axis is auto-scaled using the data
$c->addLineLayer($data, Transparent);

# Output the chart
header("Content-type: image/png");
print($c->makeChart2(PNG));
?>