The basename
function should give you what you want:
Given a string containing a path to a file, this function will return the base name of the file.
For instance, quoting the manual's page:
<?php
$path = "/home/httpd/html/index.php";
$file = basename($path); // $file is set to "index.php"
$file = basename($path, ".php"); // $file is set to "index"
?>
Or, in your case:
$full = 'F:\Program Files\SSH Communications Security\SSH Secure Shell\Output.map';
var_dump(basename($full));
You'll get:
string(10) "Output.map"