<?php

    $db_host = '';
    $db_user = '';
    $db_password = '';
    $dbName = '';

    $db = mysql_connect($db_host,$db_user,$db_password) or die(mysql_error());
    if(!$db) die(mysql_error());
    if(!mysql_select_db($dbName,$db)) die(mysql_error());

    $player_id = 6;

    $arr3d = array();

    /* Initialization to get a "dense" array
    $z_row = array_fill(0, $max_z, '<DEFAULT>');
    $y_row = array_fill(0, $max_y, $z_row);
    $arr3d = array_fill(0, $max_x, $y_row);
    unset($y_row, $z_row); // Do not waste memory
    */

    $query = "SELECT x, y, z, value FROM mapinfo WHERE id='{$player_id}'";

    $handle = mysql_query($query) or die("$query: error: " . mysql_error());

    while($row = mysql_fetch_array($handle))
    {
        // $row is an array with x, y, z and value keys in this order
        list($x, $y, $z, $value) = $row;

        /* This if we had used mysql_fetch_assoc instead
        $x = $row['x'];
        $y = $row['y'];
        $z = $row['z'];
        $value = $row['value'];
        */
        if (!isset($arr3d[$x]))
            $arr3d[$x] = array();
        if (!isset($arr3d[$x][$y]))
            $arr3d[$x][$y] = array();
        $arr3d[$x][$y][$z] = $value;
    }
    mysql_free($handle);