Show only polyline
<p>I am working on an activity tracker, at the end of the activity I have a map where I draw the polyline of the users route, I want to show only the polyline or at least draw a shadow in the map like Nike+Run does, anyone know if that's possible?, I already searched but I couldn't find out how to do it.</p>

<p>Edit:
Something like this
<a href="https://i.stack.imgur.com/0OK5W.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/0OK5W.png" alt="enter image description here"></a></p>