I guess I'll find out in phase 3 of the Alpha what these things are. Found them by accident when checking out landing on a planet with atmosphere. I can't deny that it does feel different when actually standing in front of something instead of just sitting in the SRV.
There is now also an auto-landing feature for planets, we'll see how it performs in a canyon. I remember searching for minutes for a landing spot in some difficult cases when checking out bio signals.