public final class BitmapDescriptor extends Object
  
  
  Defines a Bitmap image. For a marker, this class can be used to set the image of the
      marker icon. For a ground overlay, it can be used to set the image to place on the surface of
      the earth. To obtain a BitmapDescriptor
      use the factory class BitmapDescriptorFactory.
Example of setting the icon of a marker BitmapDescriptor.
GoogleMap map = ... // get a map.
 // Add a marker at San Francisco with an azure colored marker.
 Marker marker = map.add(new MarkerOptions()
     .position(new LatLng(37.7750, 122.4183))
     .title("San Francisco")
     .snippet("Population: 776733"))
     .icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_AZURE));