Planning altitude and avoiding obstructions

During a recent flight I literally ran into some trouble related to altitude calculations when my drone hit a tree while making its way to a mission start point. This was due to both tree height and significant altitude changes over the area to be mapped.

It would be helpful to know whether the altitude specified is relative to A) the drone launch point, B) the start of the drone’s flight plan, or C) some other reference point. In the US, I believe the legal requirement of 400ft for most flights is relative to ground level from point of launch which makes that the logical point of reference. If relative to the start of the flight plan, it would be very helpful to control which end of a flight plan is used as the start.

The desktop mission planning system already includes an elevation graph that seems to indicate the drone’s programmed altitude in blue against the route’s elevation plot (though it’s very unclear.) This information is extremely relevant when planning a flight but should also be available in the app.

When determined that the set altitude will fall below ground level some warnings should appear to recommend that the mission not be executed at all! It also stands to reason that there should be a secondary height threshold both to assist in the avoidance of common obstacles (buildings, trees, utility wires) and to ensure that the requested altitude results in useful imagery.

Has anyone else dealt with this before?

@deltaf Good questions on a lot of aspects of mission planning that I am trying to fathom for myself on the 30 say trial at the moment. From the missions flown so far it seems clear to me that the altitude is set relative to the drone launch point/Home position as the drone ascends from launch to the flight altitude I setup offline and then moves off to the start point of the flight plan at that same height and maintains that height throughout.

Without a prior recce of the flight plan area it is often difficult to choose the right altitude to avoid features. Generally I will check Google Earth coverage for obstacles such as trees and buildings, cable lines etc and I also try to find the highest possible launch point within the flight area so that I have line of sight to the drone and will generally be starting above most obstacles in the terrain. If there are mature trees I generally set altitude at 100 - 150 feet (I fly low for high resolution on archaeological sites). Today I had to estimate how high ruinous masonry was on the site and pick a high point that let me fly at 100 ft and cleared the masonry. Sometimes if I get to the site and find I have set the altitude too low to clear objects in the flight path I change the altitude in the DD setting option before starting the flight.

The elevation graph is unclear to me also and more explanation on this from DD would be appreciated. I also assumed the blue line is flight altitude and green is the ground surface, but not sure.

Hello everybody;

Anybody knows a special gesture to do in DD latest app in order to increase the max Alt of 122 m (400 ft) like in Map Pilot App whereas we can press more than 8 sec on the Slider in order to change it to 300 m ?

I need to fly my P3P at 160 m.


Did you try to set the altitude limit in the DJI app first?

It is already set at 500 m