source: trunk/xgraph/jpgraph/Examples/matrix_ex01.php

<?php
require_once ('jpgraph/jpgraph.php');
require_once ('jpgraph/jpgraph_matrix.php');

$data = array(
        array(0,1,2,3,4,5,6,7,8,9,10),
        array(10,9,8,7,6,5,4,3,2,1,0),
        array(0,1,2,3,4,5,6,7,8,9,10),
        array(10,9,8,17,6,5,4,3,2,1,0),
        array(0,1,2,3,4,4,9,7,8,9,10),
        array(8,1,2,3,4,8,3,7,8,9,10),
        array(10,3,5,7,6,5,4,3,12,1,0),
        array(10,9,8,7,6,5,4,3,2,1,0),
);

// Do the meshinterpolation once for the data
doMeshInterpolate($data,3);

$graph = new MatrixGraph(550,500);
$graph->title->Set('Possible legend positions');
$graph->title->SetFont(FF_ARIAL,FS_BOLD,14);

$mp = array();
$n = 4;
$pos = array(0.3,0.33, 0.8,0.68, 
                         0.3,0.68, 0.8,0.33);
for($i=0; $i < $n; ++$i){
    $mp[$i] = new MatrixPlot($data);
    $mp[$i]->colormap->SetMap($i);
        $mp[$i]->SetModuleSize(4,5);
        $mp[$i]->SetLegendLayout($i);
        $mp[$i]->SetCenterPos($pos[$i*2],$pos[$i*2+1]);
}

$graph->Add($mp);
$graph->Stroke();

?>