I live in the mountains where the only flat land is along rivers. I do a ton of flying over said rivers. They are all very rocky, clear and 1-5 feet deep.
Anyhow, it’s my understanding that no matter the altitudes I enter in my waypoint mission, they will always be relative to where I take off from. Where I take off from is 0. So I can’t physically go to the river, create a mission manually, and run that mission from home where I am a couple hundred feet higher than where I was when I created the mission, correct?
Does the “use online altitude”…help with this?
FYI- I just checked out the Litchi Above-Ground to Google Elevation Converter …it says none of my elevations are above ground…with or without online altitude checked.
Thanks for any help!
That is correct.
If I am properly understanding what you describe, you are correct. You cannot move to a location where take-off ground elevation is different from the ground elevation under waypoint #1 of your original mission.
Here is a visual description of how the “Above Ground” option works:
That converter is used to employ Google’s terrain elevation data instead of the elevation data that Litchi uses.
Thanks Wes. Quick follow-up… what if I create on mission hub a mission that is all 100’ altitude above a river. Then I take off from several hundred feet above the river and fly the drone down to a few feet of altitude and update my home point. And then hit go on the waypoint mission. Would that, within a few feet, fix the altitude issue?
No, that will not reset the “take-off altitude”. I’m 95% sure that resetting your home point does not reset the altitude.
A couple work-arounds could be use, though:
- If you placed your first waypoint up near your launch point so that the ground elevation under that first waypoint matched that of where you take off, then all of your waypoint heights will be as specified.
- If you flew down to the river and landed the drone (in a safe and viewable location) then took-off again, that will reset your take-off altitude to zero. There is some risk with this method so only try it if the conditions allow it.
No matter how you do this, I see some risk in this type of flight. It would be wise to perform some simple and safe tests before attempting a mission where waypoints will bring the drone hundreds of feet down into a canyon.