Are DJI Waypoint heights dependent upon launch point height?

Although I’ve had my M2Z for over 20 months, Ive done very little with its waypoints feature - Until Now that is.
They’ve just started building a large housing project around 1/2 mile away, so i thought it would be interesting to fly say once a week on the exact same route and maybe work out how to make some kind of ‘rapid build’ video in a years time.
So Ive watched a few videos on creating waypoints but still have a few unanswered questions.
I programmed a possible route whilst in my garden earlier today - What is that red dot around 50m from my house
When I got to the launch point at the top of the field, there was still a line joined to my garden?
If I’ve set all the waypoints to say 40m, what happens if circumstances change & I have to take off from the bottom of the field which is around 10m lower than the top of the field - will all waypoints now be 10m lower than they were on previous flights?
At the moment Im changing the waypoint heights and gimbal angle on an individual basis, is it possible to do a universal change?


I use DroneDeploy and Pix4D for surveys and they are launch point relative not absolute heights so i guess its the same in Go4.

It’s a simple thing to test though in one flight.

Reason being the drone uses baro altitude above launch as its far more accurate than GPS altitude (which can be 30m out at times for various reasons).

They are above take off height yes.

Litchi lets you set above ground level (AGL)

I bought Litchi and have programmed in a few flights, but I found it only lets you set ‘Height above Ground Level’ in the areas where it has full mapping data, which unfortunately didnt cover the area I was flying around.
Not a big problem though if I always take off from the same spot