title: Add layer above googlemaps layer in swift
body: <p>I tried to add my own layer on google maps by code from google maps documentation:</p>
  
  <pre><code>extension MapViewController {
  func addTiles() {
      // Implement GMSTileURLConstructor
      // Returns a Tile based on the x,y,zoom coordinates, and the requested floor
      let urls = { (x: UInt, y: UInt, zoom: UInt) -&gt; NSURL in
          let url = "http://example.pl/ras/\(zoom)/\(x),\(y).v\(1).png";
  
          return NSURL(string: url)!
      }
  
      // Create the GMSTileLayer
      let layer = GMSURLTileLayer(URLConstructor: urls)
      layer.tileSize = 512
      layer.map = mapView
  }}
  </code></pre>
  
  <p>I got smth like this:</p>
  
  <p><a href="https://i.stack.imgur.com/33jab.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/33jab.png" alt="enter image description here"></a></p>
  
  <p>I don't see terrain which should be under my tile. My tiles are transparent. Do you have any idea what can be wrong?</p>
  
  <p>Update: 
  Problem is occurring only on the iOS simulator. It is working on real devices.</p>