Greetings -
  Quick question, just need a little insight here.

  I am flying over my subject at 20 feet which suggests that the VPS (Visual Positioning System) is most likey controlled by the visible and IR sensors on the bottom of the M2P (at least this is what I have heard/read - I am new at all of this).  However, when looking at data logs I noted that the VPS in PhantomHelp shows VPS = 19-25 ft (the terrain is high on one end and does drop about 5 ft over 300 ft) whereas in AirData's "sensor" readout the elevation appears to be steady at 19.7 ft which is equal to the "6m" height set in the mission hub.  As a first guess I would say since the IR/Vis spectrum is used for altitude shouldn't it stick to a mission hub height?  Or would one want to add waypoints to adjust to raising/lowering the flight path a few feet.  I am trying to do an orthomap - though I am not that high (so parallax issues, etc).

  If I am flying 20 or so feet is the VPS altitude controlling (v. barometric)? and if so which of the readouts is closer to true, DJI PhantomHelp or AirData?  If you need to see data, logs etc. I can post them.  Just curious thanks in advance.

Hello there Lemire559. Good day and thank you for the inquiry. Since this are 3rd party applications. I hope that you will get the best recommendation from our DJI co pilots with regards to this matter. Just a reminder to please use the DJI Go 4 when flying your DJI Mavic 2 Pro for compatibility and reliability purposes. Thank you and have a safe flight always.