I'm certain I saw something regarding this before but cannot seem to locate it any longer.

Let's say that you are on top of a large hill or standing near a fairly decent drop-off point (edge of a cliff for example). You take off and rise to 30 meters or so. Then you move horizontally in another direction toward the bottom of the hill or over the cliff's edge without changing your actual altitude. Now the drone is 200 meters away and obviously much further in height from the actual ground now than when you took off. Then you lower the drone to a point much lower down that hill than that which was recorded upon your take-off point. What kind of feedback would you be receiving as to your exact height? Negative numbers or would the elevation reading change as the terrain does?

Negative numbers is what you will get.

Thank you.

The altitude displayed at the bottom of DJI GO is always the altitude above (or below in this case) the takeoff point.

Hi, thanks for the inquiry. The current altitude of your aircraft can be monitored on the DJI Go 4 application. Apparently, flying the drone lower than your take-off point should've given you negative numbers.  Please let us know if you have other concerns. Thank you for continued support.

Thanks for the replies. Haven't done it yet, but just wondering what would happen if I did......