Hi, I would like to know if while performing a flight mission to get a photograhic coverage according to a previous plan (DJI light planner) the drone will fly at the same altitude above mean sea level regardless of the terrain topography or at a given height above the terrain going up and down according to the hills and valleys?

The drone will fly at the altitude you set in the mission. That altitude is the altitude above the takeoff point. The drone doesn't know where the ground is located, so it's not able to automatically adjust its altitude to follow the terrain below.

msinger Posted at 11-23 10:24
The drone will fly at the altitude you set in the mission. That altitude is the altitude above the takeoff point. The drone doesn't know where the ground is located, so it's not able to automatically adjust its altitude to follow the terrain below.

What about terrain follow (that I have just found out)? It seems, as I expected, that the sensors might detect the ground and keep a distance from it.

Terrain Follow might be an option if you're flying close to the ground and the terrain does not slope downward.

msinger Posted at 11-24 12:04
Terrain Follow might be an option if you're flying close to the ground and the terrain does not slope downward.

Thanks

So you mean the drone will change the flight height above terrain going up hill but will not come down going down hill.

You refer "close to the ground". Can you quantify? Is it 10m, 100m?

The idea is to make several stripes of photographs at the same "scale" (so I need to keep approximately the same distance to the object)

The aircraft will maintain its height during the flight and ascend if the ground below slopes upward. However, it will never descend if the ground slopes downward.

Terrain Follow mode uses the downward sensors to detect the ground, so you need to fly within the detection range (usually between 1 to 10 meters).

msinger Posted at 11-23 10:24
The drone will fly at the altitude you set in the mission. That altitude is the altitude above the takeoff point. The drone doesn't know where the ground is located, so it's not able to automatically adjust its altitude to follow the terrain below.

Thanks for the info.