--- a/labs/busstopdensity.tile.php
+++ b/labs/busstopdensity.tile.php
@@ -1,1 +1,121 @@
+<?php
+include ('../include/common.inc.php');
+$debugOkay = Array();
 
+/*
+*DISCLAIMER
+*  http://blog.gmapify.fr/create-beautiful-tiled-heat-maps-with-php-and-gd
+*THIS SOFTWARE IS PROVIDED BY THE AUTHOR 'AS IS' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES *OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, *INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF *USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT *(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+*	@author: Olivier G. <olbibigo_AT_gmail_DOT_com>
+*	@version: 1.0
+*	@history:
+*		1.0	creation
+*/
+	set_time_limit(120);//2mn
+	ini_set('memory_limit', '256M');
+error_reporting(E_ALL ^ E_DEPRECATED);
+	require_once ('lib/GoogleMapUtility.php');
+	require_once ('lib/HeatMap.php');
+
+	//Root folder to store generated tiles
+	define('TILE_DIR', 'tiles/');
+	//Covered geographic areas
+	define('MIN_LAT', -35.48);
+	define('MAX_LAT', -35.15);
+	define('MIN_LNG', 148.98);
+	define('MAX_LNG', 149.25);
+	define('TILE_SIZE_FACTOR', 0.5);
+	define('SPOT_RADIUS', 30);
+	define('SPOT_DIMMING_LEVEL', 50);
+	
+	//Input parameters
+	if(isset($_GET['x']))
+		$X = (int)$_GET['x'];
+	else
+		exit("x missing");
+	if(isset($_GET['y']))
+		$Y = (int)$_GET['y'];
+	else
+		exit("y missing");
+	if(isset($_GET['zoom']))
+		$zoom = (int)$_GET['zoom'];
+	else
+		exit("zoom missing");
+
+	$dir = TILE_DIR.$zoom;
+	$tilename = $dir.'/'.$X.'_'.$Y.'.png';
+	//HTTP headers  (data type and caching rule)
+	header("Cache-Control: must-revalidate");
+	header("Expires: " . gmdate("D, d M Y H:i:s", time() + 86400) . " GMT");
+	if(!file_exists($tilename)){
+		$rect = GoogleMapUtility::getTileRect($X, $Y, $zoom);
+		//A tile can contain part of a spot with center in an adjacent tile (overlaps).
+		//Knowing the spot radius (in pixels) and zoom level, a smart way to process tiles would be to compute the box (in decimal degrees) containing only spots that can be drawn on current tile. We choose a simpler solution by increeasing  geo bounds by 2*TILE_SIZE_FACTOR whatever the zoom level and spot radius.
+		$extend_X = $rect->width * TILE_SIZE_FACTOR;//in decimal degrees
+		$extend_Y = $rect->height * TILE_SIZE_FACTOR;//in decimal degrees
+		$swlat = $rect->y - $extend_Y;
+		$swlng = $rect->x - $extend_X;
+		$nelat = $swlat + $rect->height + 2 * $extend_Y;
+		$nelng = $swlng + $rect->width + 2 * $extend_X;
+
+		if( ($nelat <= MIN_LAT) || ($swlat >= MAX_LAT) || ($nelng <= MIN_LNG) || ($swlng >= MAX_LNG)){
+			//No geodata so return generic empty tile
+			echo file_get_contents(TILE_DIR.'empty.png');
+			exit();
+		}
+
+		//Get McDonald's spots
+		$spots = fGetPOI('Select * from stops where
+				(stop_lon > '.$swlng.' AND stop_lon < '.$nelng.')
+			AND (stop_lat < '.$nelat.' AND stop_lat > '.$swlat.')', $im, $X, $Y, $zoom, SPOT_RADIUS);
+
+		
+		if(empty($spots)){
+			//No geodata so return generic empty tile
+			header('Content-type: image/png');
+			echo file_get_contents(TILE_DIR.'empty.png');
+		}else{
+			if(!file_exists($dir)){
+				mkdir($dir, 0705);
+			}
+			//All the magics is in HeatMap class :)
+			$im = HeatMap::createImage($spots, GoogleMapUtility::TILE_SIZE, GoogleMapUtility::TILE_SIZE, heatMap::$WITH_ALPHA, SPOT_RADIUS, SPOT_DIMMING_LEVEL, HeatMap::$GRADIENT_FIRE);
+			//Store tile for reuse and output it
+			header('content-type:image/png;');
+			imagepng($im, $tilename);
+			echo file_get_contents($tilename);
+			imagedestroy($im);
+			unset($im);
+		}
+	}else{
+		//Output stored tile
+		header('content-type:image/png;');
+		echo file_get_contents($tilename);
+	}
+	/////////////
+	//Functions//
+	/////////////
+	function fGetPOI($query, &$im, $X, $Y, $zoom, $offset){
+            global $conn;
+		$nbPOIInsideTile = 0;
+
+	$result = pg_query($conn, $query);
+        $spots = Array();
+	if (!$result) {
+		databaseError(pg_result_error($result));
+		return Array();
+	}
+	foreach( pg_fetch_all($result) as $row){
+				$point = GoogleMapUtility::getOffsetPixelCoords($row['stop_lat'], $row['stop_lon'], $zoom, $X, $Y);
+				//Count result only in the tile
+				if( ($point->x > -$offset) && ($point->x < (GoogleMapUtility::TILE_SIZE+$offset)) && ($point->y > -$offset) && ($point->y < (GoogleMapUtility::TILE_SIZE+$offset))){
+					$spots[] = new HeatMapPoint($point->x, $point->y);
+				}
+				
+			}//while
+		return $spots;
+	}//fAddPOI
+?>
+
+