Get terrain height data based on position

Give an arbitrary point in a mission would I be able to determine the height of the terrain at said point? What I would like to do is spawn random ai players around the map but of course I want to be sure those players are not going to end up underneath the terrain. I could do this using spawn spheres and I have seen some discussion on that. What I am curious of is if you can do the same kind of thing without the aid of a spawn sphere.