Tile utility class Handles converting slippy map tile numbers to lat/lon values Ported from: http://wiki.openstreetmap.org/wiki/Slippy_map_tilenames#Java

Util_Tile.php

<?php
/**
 * Tile utility class
 * 
 * Handles converting slippy map tile numbers to lat/lon values
 * Ported from:
 * http://svn.openstreetmap.org/applications/routing/pyroute/tilenames.py
 * http://wiki.openstreetmap.org/wiki/Slippy_map_tilenames#Java
 */
class Util_Tile {
	
	/**
	 * Get number of tiles for whole map
	 * @param int $zoom
	 * @return int number of tiles
	 */
	public static function numTiles($zoom)
	{
		return pow(2, $zoom);
	}
	
	/**
	 * Get the bounding box for a set of tile values
	 * 
	 * @param int $zoom
	 * @param int $x
	 * @param int $y
	 * @return BoundingBox 
	 */
	public static function tileToBoundingBox($zoom, $x, $y)
	{
		$bb = new BoundingBox();
		$bb->north = self::tileToLat($y, $zoom);
		$bb->south = self::tileToLat($y + 1, $zoom);
		$bb->west = self::tileToLon($x, $zoom);
		$bb->east = self::tileToLon($x + 1, $zoom);
		return $bb;
	}
	
	/**
	 * Get longitude from tile x value
	 * 
	 * @param int $x
	 * @param int $zoom
	 * @return float longitude
	 */
	public static function tileToLon($x, $zoom)
	{
		return $x / self::numTiles($zoom) * 360.0 - 180.0;
	}
	
	/**
	 * Get latitude from tile x value
	 * 
	 * @param int $y
	 * @param int $zoom
	 * @return float latitude
	 */
	public static function tileToLat($y, $zoom)
	{
		$n = pi() * (1 - 2 * $y / self::numTiles($zoom));
		return rad2deg(atan(sinh($n)));
	}
	
}

/**
 * Bounding Box class
 */
class BoundingBox {
	public $north;
	public $south;
	public $east;
	public $west;
}