diff --git a/tileserver.php b/tileserver.php
index fc1eda3..96ffaea 100644
--- a/tileserver.php
+++ b/tileserver.php
@@ -189,11 +189,32 @@ class Server {
         ? 'jpg'
         : 'png';
     }
+    // autodetect bounds
+    if (!array_key_exists('bounds', $metadata)) {
+      $result = $this->db->query('select min(tile_column) as w, max(tile_column) as e, min(tile_row) as s, max(tile_row) as n from tiles where zoom_level='.$metadata['maxzoom']);
+      $resultdata = $result->fetchAll();
+      $w = -180 + 360 * ($resultdata[0]['w'] / pow(2,$metadata['maxzoom']));
+      $e = -180 + 360 * ((1+$resultdata[0]['e']) / pow(2,$metadata['maxzoom']));
+      $n = $this->row2lat($resultdata[0]['n'], $metadata['maxzoom']);
+      $s = $this->row2lat($resultdata[0]['s']-1, $metadata['maxzoom']);
+      $metadata['bounds'] = implode(',', array($w, $s, $e, $n));
+    }
     $metadata = $this->metadataValidation($metadata);
     $mbt = explode('.', $mbt);
     $metadata['basename'] = $mbt[0];
     return $metadata;
   }
+  
+  /**
+   * Convert row number to latitude of the top of the row
+   * @param integer $r
+   * @param integer $zoom
+   * @return integer
+   */
+   public function row2lat($r, $zoom) {
+     $y = $r / pow(2,$zoom-1) - 1;
+     return rad2deg(2.0 * atan(exp(3.191459196*$y)) - 1.57079632679489661922);
+   }
 
   /**
    * Valids metaJSON
@@ -202,7 +223,6 @@ class Server {
    */
   public function metadataValidation($metadata) {
     if (array_key_exists('bounds', $metadata)) {
-// TODO: Calculate bounds from tiles if bounds is missing - with GlobalMercator
       $metadata['bounds'] = array_map('floatval', explode(',', $metadata['bounds']));
     } else {
       $metadata['bounds'] = array(-180, -85.051128779807, 180, 85.051128779807);
@@ -210,7 +230,6 @@ class Server {
     if (!array_key_exists('profile', $metadata)) {
       $metadata['profile'] = 'mercator';
     }
-// TODO: detect format, minzoom, maxzoom, thumb / scandir() for directory
 // TODO: detect thumb / SQL for mbtiles
     if (array_key_exists('minzoom', $metadata))
       $metadata['minzoom'] = intval($metadata['minzoom']);
@@ -223,11 +242,6 @@ class Server {
     if (!array_key_exists('format', $metadata)) {
       $metadata['format'] = 'png';
     }
-    /*
-      if (!array_key_exists('profile', $metadata )) {
-      $metadata['profile'] = 'mercator';
-      }
-     */
     return $metadata;
   }