# PHPlot Example - Horizontal Error Plot
require_once 'phplot.php';
# The experimental results as a series of temperature measurements:
$results = array(98, 102, 100, 103, 101, 105, 110, 108, 109);
# The accuracy of our measuring equipment is +/- 5%
$error_factor = 0.05;
# Convert the experimental results to a PHPlot data array for error plots.
function reduce_data($results, $error_factor)
{
# Use the average of measurements to approximate the error amount:
$err = $error_factor * array_sum($results) / count($results);
# Build the 'data-data-yx-error' data array:
$data = array();
$i = 1;
foreach ($results as $value) {
$data[] = array("Sample {$i}", $i++, $value, $err, $err);
}
return $data;
}
$plot = new PHPlot(800, 600);
$plot->SetTitle('Experiment Results');
$plot->SetXTitle('Melting Temperature (degrees C)');
$plot->SetDataValues(reduce_data($results, $error_factor));
$plot->SetDataType('data-data-yx-error');
$plot->SetPlotType('points');
$plot->SetYTickPos('none');
$plot->SetImageBorderType('plain');
// Improves presentation in the manual
$plot->SetPlotAreaWorld(80);
$plot->DrawGraph();
{
$n = count($row);
$p = $k * ($n - 1);
if ($p == (int) $p) {
return $row[$p];
}
return ($row[(int) $p] + $row[(int) ($p + 1)]) / 2;
}
# Convert the experimental results to a PHPlot data array.
function reduce_data($results)
{
$data = array();
foreach ($results as $label => $row) {
$n_samples = count($row);
sort($row);
$data[] = array("{$label}\n({$n_samples} Samples)", $row[0], kpercentile($row, 0.25), kpercentile($row, 0.5), kpercentile($row, 0.75), $row[$n_samples - 1]);
// Maximum
}
return $data;
}
$plot = new PHPlot(800, 600);
$plot->SetTitle('Box Plot (without outliers)');
$plot->SetDataType('text-data');
$plot->SetDataValues(reduce_data($results));
$plot->SetPlotType('boxes');
# These 2 lines make tick marks line up with text-data data points:
$plot->SetXTickIncrement(1);
$plot->SetXTickAnchor(0.5);
$plot->SetImageBorderType('plain');
// Improves presentation in the manual
$plot->DrawGraph();
