You cannot draw on top of a native.newMapView() nor can you draw on top of a native.newWebView (for using Google Maps instead of the default map SDK). Google maps might have some routing information, but there isn’t a way with Corona SDK to take GPS data and draw on a map in real time. You would need Enterprise for this.
Now it might be possible if you’re trying to generate a map like Runkeeper does after your run is done, to feed the GPS points to the Google Maps API and have it render the lines as part of the map. Key word is “Might”. But we still don’t support Corona SDK running in the background.
Rob