         assert(size.width  <= 640 * (retina ? 1 : 2), "maximum width is 1280px (640px for retina)")
         assert(size.height <= 640 * (retina ? 1 : 2), "maximum height is 1280px (640px for retina)")
 
-        assert(countElements(overlays) <= 100, "maximum number of overlays is 100")
+        assert(count(overlays) <= 100, "maximum number of overlays is 100")
 
         var requestURLString = requestURLStringBase
         requestURLString += mapID

    }

    private class func allowedCharacterSet() -> NSMutableCharacterSet {
        let characterSet = NSCharacterSet.URLQueryAllowedCharacterSet().mutableCopy() as NSMutableCharacterSet
        characterSet.removeCharactersInString("/")
        return characterSet
    }


            var output = encodeCoordinate(coordinates[0].latitude) + encodeCoordinate(coordinates[0].longitude)

            for var i = 1; i < count(coordinates); ++i {
                let a = coordinates[i]
                let b = coordinates[i - 1]
                output += encodeCoordinate(a.latitude - b.latitude)
