google earth - KML Show direction of movement on line -

in google earth kml generate i'm trying indicate direction of movement along linepath arrow. such, each data point on line made palace mark, in specified arrow icon in style, , added heading element it. style section each place mark looks this:

<style>     <iconstyle>         <icon>             <href>...<href>         </icon>         <heading>[appropriate heading point]</heading>     </iconstyle> </style> 

and works great when viewing path top-down perspective:

as can see, arrows point along path in direction of movement, desired. however, if try view path more oblique angle, i.e. looking along path or across path rather down @ path, things change:

now instead of pointing along path, arrows pointing angled downwards. correct, icons need rotated several degrees counter-clockwise. using same kml in both views, viewing angle in google earth has changed. how can fix this?

if view icons looking straight down heading correct once @ scene in 3-d tilt icons tilt accordingly.

to have arrow in direction of heading best approach using kml represent point data in track element assuming have timestamp each point. heading, speed, etc. calculated each waypoint , arrow direction points in direction based on current time in time slider.

tracks can viewed elevation profile showing both elevation , speed.

you can find track example here.