I am trying to show depth/height of billboards
Showing the z-axis of billboards representing real life objects in 3D space is difficult without references. For example, tracking of moving aircrafts.
I tried using czml polyline (vertical line from sea level to the object to indicate depth/height when user zoom to a certain level) in z-direction but updating its position along with the billboard seems to be slow. It was probably because instead of just updating the cartesian location, it is redrawing the polyline each time.
Any suggestion on how to place a line or ruler along side a moving billboard at a reasonable performance?