As far as I can tell, the vertical height indicator in the DJI Go App will only tell me how high the drone is from the takeoff point.       That's a problem for me when flying in a hilly terrain.      Particlarly when it tells me I've reached the maximum height allowed and I'm about to run into a tree as I come to the top of a hill.     Or, when I'm flying down to a lake in a valley and don't want to accidentally land in it.   

So, I know that the drone has sensors that tell it how high it is off the ground.     It even has a flight mode to tell it to keep a constant height.    But my question is:  is there any way to get it to tell me how high it is?

Thanks!

VPS will give you an estimate of your current AGL height when it's enabled and when you're close enough to the ground for it to work and that value shows up at the bottom of the DJI Go 4 app during flight. But when you're flying too high for VPS to work or it's otherwise disabled there's no way to display the current AGL height.

VPS is the most accurate height above ground, but only works within about 40 feet of ground.  It is also only accurate above  a fairly flat surface - ground vegetation and trees will interfere.