<?php
if (isset($_REQUEST['config'])) {
    $config = $_REQUEST['config'];
    $startFile = "map_" . $config . ".phtml";
    if (file_exists($startFile)) {
        $startFile = "$startFile?config=$config";
    } else {
        $startFile = "map.phtml?config=$config";
    }
} else {
    $startFile = "map_default.phtml";
}

header("Location: $startFile");
?>