Confused about starting altitude

[NormanS]

I have been reading the various posts about AGL. I am very new to the drone world so if I have missed something or a setting please point me in the right direction.

When I start a flight I wait for a good gps number. I set the home point and my SC advises it is set. When I take off and go to a known altitude of 60ft the display only shows 15 ft. When I decend the numbers go negative.

Any suggestions? Before you ask, I am struggling to find the flight.txt file. Where is?

I have a M2Z and SC and obviously very little brain.

Thanks in advance for guidance.

I live overlooking the site of the 1st battle of the British civil war with spectacular views of over 70 Miles. I will post a picture.

 

[old man mavic]

@NormanS the height displayed on the screen is only an approximate reading ,based on barometric pressure once the drone goes above a certain height above its take off point ,and its quite normal for it to go to a minus number when the drone goes below the take off point
it is not an very accurate reading at the best of times, and can vary with the wind speed dont take off until you have got the green light and the message about the home point ,the max height above AGL is shown only at the take off point if you fly out over a valley where the ground drops away then you will have to reduce altitude to stay within the max AGL

 

[Camino Ken]

IMHO that amount of discrepancy is not normal unless you have a rapidly changing barometric pressure due to a storm coming or going. I typically get a few feet of error and a max of 5-6ft. Something seems amiss.

 

[iamcostas]

This photo shows a magnificent place to live ?

 

[Peterson]

My M2P to my knowledge has not done this. It does not seem normal in my opinion. However I live on flat ground and have not had the ability to fly into valleys to show a negative altitude. I realize it is just a tool and not 100% but IMO it is pretty close.