litchi mission almost drove my P3 into a cliff

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I used Litchi to create a mission over some mountains - gimbal pitch disable and heading on manual, so that I can point the camera as the mission proceeds. I used the "above ground" feature so that every waypoint would be the same height AGL. I used a LOT of waypoints, close together, as I didn't want to get caught crashing into some pointy bit of rock. I checked the mission by exporting a KML to Google Earth to confirm clearances.

Apparently all that was not enough - see the video. I bailed out of the mission at literally THE LAST SECOND.

I now have to wonder - is it more accurate to create this sort of mission "the old fashioned way", using Google Earth as the basis for the waypoints, and then import into Litchi? I was under the impression that the data using either method comes from the same place, and that the results would be the same. Now I wonder...

Please let me know your impressions about all this. Did I not use enough waypoints?

I edited the elevation AGL on a lot of the waypoints after this experience and flew the mission without incident, though it surely seemed like I was closer to the ground than I expected to be in a lot of places. Hmmmm…...

 
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I edited the elevation AGL on a lot of the waypoints after this experience and flew the mission without incident, though it surely seemed like I was closer to the ground than I expected to be in a lot of places
I have not looked at the video as of yet, however, looking only at the sample graphic above, did you have signal loss during the mission at any point? Your vertical altitude lines are not linear. This could be part of your editing but I am asking the question anyway. Also, the barometer in the Phantom is not that accurate, nor is Google Earths representation of such. Allway's add at least an additional 20 feet above your planned altitude, just for the error in the barometer reporting. If you can pull the aircraft .dat file for this flight we can most likely tell you where the issue lies. Also, when posting issues with Litchi, please include a link to the mission profile from the hub. Lastly, if you decide to look at the additional data and are not familiar with the process you will need to retrieve the aircrafts's .dat by following the instructions on the link below. Then share a link back here to that. You will need to upload the retrieved file to a share site such as Drobox, Google Drive etc... to be able to share that here. They are quite large files. Link is below if interested.

Retrieve Dat File
 
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I think Google Earth elevations are not super accurate, and may be more generalized across an area. In the video, you can see the hillside suddenly jut upward in the form of a rock outcrop. I'm guessing the hillside may continue it's slopped ascent beyond that outcrop as your waypoints reflect, but either Google Earth did not pick up the sudden increase in terrain at that point, or a waypoint just didn't happen to fall there and Litchi just assumed a constant slope between.
 
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60 feet is only 18.3 m AGL I moved the path of one of my missions that was 18m AGL from a valley to a ridge line and my P3 didn't make it over the highest point (soft landing into a canola crop luckily )
The way GE ground elevation are measured results in an average over a 30m radius apparently so sudden changes in ground elevation will not be well represented.
I checked the GE elevation of a TRIG station near us and this point was 11.5m higher than GEs figure .
As FD said add 20 feet at least then review your footage carefully to work out where GE is not telling you the truth.
 
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60 feet is only 18.3 m AGL I moved the path of one of my missions that was 18m AGL from a valley to a ridge line and my P3 didn't make it over the highest point (soft landing into a canola crop luckily )
The way GE ground elevation are measured results in an average over a 30m radius apparently so sudden changes in ground elevation will not be well represented.
I checked the GE elevation of a TRIG station near us and this point was 11.5m higher than GEs figure .
As FD said add 20 feet at least then review your footage carefully to work out where GE is not telling you the truth.
Clearly I put too much trust in the elevations provided. I was not aware of that 30m radius average. That's a big deal when dealing with outcrops and such! I THOUGHT I added enough extra waypoints to avoid missing such features, but given the averaging that GE apparently does, in that case no matter how tightly I packed the WPs, they would be working with averages and not actual elevations. UGH.

FWIW here's my mission. The outcrop is at WP 13. Mission Hub - Litchi

I tweaked the mission and re-flew it with no problems after that almost fateful trip. I will post that video, and also the .dat file that fly dawg requested when I can.
 
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I still need to uncover the .dat file, but for now, here's the edited flight - the second trip, all AGL numbers increased by at least 80 feet on location. Considering that the AC seems to fly really low from time to time in this video, it makes me think that a LOT of the numbers on the original mission were way off. Enjoy:

 
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You were lucky you were able to stop it the first time while still in range .If it had cleared the first obstacle there were plenty more lined up. Very nice scenery and an ambitiousmission.
 
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I have found that after rising over 100ft. or so, further along a mission the reported altitudes are off, sometimes over 50ft. Is that Aridzona?
 
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I have found that after rising over 100ft. or so, further along a mission the reported altitudes are off, sometimes over 50ft. Is that Aridzona?
I don't get why the reported altitudes would be incorrect as one goes higher.
Yes, Canyon Lake, about an hour east of Phoenix. Inside of Tonto National Forest.
 
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Hello @Steve_in_NJ.
@The Springs sent me a link to this thread.

OMG, Trees are more forgiving then those rocks. ;)
Glad you didn't have to retrieve it!

Your shared mission you posted doesn't come up, did you change it?
Could anybody else view it?

I'm looking through this thread kind of in a hurry.
If you didn't loose signal than your mobile device has a good log.
crApples are a pain to retrieve the files from, I use an iPad, iPhone but not a Mac so I'm always frustrated. (You have to use iTunes)

Downloading the .dat files is not fun either, but if you haven't done it before with a working bird, it is even more frustrating.

I would like to see one of your missions or both.

I really wish @VegasFlyer would show up again, its been since June!
My most daring mission!

Rod
 
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@Steve_in_NJ

Your posted mission doesn't come up, Would really like to see it.

Rod
 

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