Litchi waypoint altitude transition

[modbuilder]

I've had the same experience as the OP but with a Mavic Pro and Litchi after setting it up with Virtual LItchi Mission and Google Earth Pro. Fortunately I saw the top of the tree approaching during the actual autonomous flight in time to intervene.

In my investigation into what went wrong, I concluded that Google Earth Pro terrain elevations can be excellent on hard surfaces like roads and parking lots, but can be off too much to trust for this purpose in wooded areas. I ran a thread about it on the MP Pilots forum and had the usual responses with some agreeing and some taking exception, even strong exception, based on their individual experiences.

Since then, I've added some changes to my Litchi mission set ups that have helped. One change is that the first time I fly the WP mission, I fly it with the camera facing forward into the flight so I can see what's coming. I also fly it pretty slowly to give me a chance to react. I also try to go up and just take a look around with the camera to see how the terrain changes.

Love LItchi by the way. Use it all the time for commercial photo missions in construction projects.

 

[kyrvas]

According to L. Seberini, who authors the Phantom Film School series on Udemy, "

• Google elevation data can be off, so apply some extra room to ensure you avoid obstacles
  
  
• - It only does RTG at the WP’s and NOT between WP’s - be aware of obstacles between WP’s"
  
  My personal experience during one planned mission:
  with Google Earth the HP / WP1 was at elevation 4914'
  with Garmin GPS at HP / WP1 the elevation was 4944'
  
  So, there was a discrepancy in elevation of 30'; therefore since GE was lower I had to at least add 30' to my starting HP altitude.
  
  Regarding trees: it may help to go online, if your not a dendrologist, to search for the heights of the trees in your area; for instance, white oaks, and ponderosa pines have different mature heights of about 20' but those heights can change in different locales. On the Arborday.org site, the ponderosa is listed at about 90' "in city conditions"; although in Oregon there is a ponderosa in the 268' range. Go figure . . .
  
  I like @modbuilder approach to fly the location with camera views before committing to autonomous flights.

 

[Geoff44]

Thank you, that helps and gives me a few places to start. The mission seems stupidly ambitious now, it wasn't a good place to have it all go wrong.

Looks like just a matter of not enough height.
I have flown a number of farm missions in similar terrain.
In the past I have been able to open google earth pro in Queensland Globe where I could ad property boundaries and (10m)contours. Then construct each waypoint on each contour.
Weigh point height, at 40 meters for the highest tree plus 25 meters above the ground total 65 meters above each weigh point with never a problem sometimes losing connection then waiting for p4p to complete mission and come back into range with good video footage. I never had a problem until I started to come under the 65 meters down to 40m and collected a tree on very steep hillside.
With others comments about google earth can be 10m out I will be going to 75 m in future in steep terrain.
Also flying the first time round the mission with camera level is good.

Queensland Globe has this month gone away from using google earth pro to another mapping service with no way to construct missions.
Can any one please advise if there is another way to put contours and property boundaries onto google earth pro. Or another system that will do the same.
Also have fitted trackimo to p4p incase of fly away or similar incident.

 

[The Springs]

It might be too late now but did you try getting up on high ground and giving the find my drone function a go .

 

[RodPad]

@Osmosis,
"65' AGL?? Most trees are 80' and some pines can reach 110-120' I always fly at a minimum of 150' and even then the trees appear very close.."

Pine trees 110-120' ?
I wish, 200' mission.

When the Phantom Magnet (Tree) let it go, it was in five pieces.

My missions NOW are 100 meters AGL, then I fine tune later.

@kyrvas,
"although in Oregon there is a ponderosa in the 268' range. Go figure . . ."

@modbuilder,
"Love LItchi by the way. Use it all the time for commercial photo missions in construction projects."
Yes!

OK, enough chatter.
@mjlp,
Whats up man, need some help searching.

Rod

 

[kyrvas]

Looks like just a matter of not enough height.
I have flown a number of farm missions in similar terrain.
In the past I have been able to open google earth pro in Queensland Globe where I could ad property boundaries and (10m)contours. Then construct each waypoint on each contour.
Weigh point height, at 40 meters for the highest tree plus 25 meters above the ground total 65 meters above each weigh point with never a problem sometimes losing connection then waiting for p4p to complete mission and come back into range with good video footage. I never had a problem until I started to come under the 65 meters down to 40m and collected a tree on very steep hillside.
With others comments about google earth can be 10m out I will be going to 75 m in future in steep terrain.
Also flying the first time round the mission with camera level is good.

Queensland Globe has this month gone away from using google earth pro to another mapping service with no way to construct missions.
Can any one please advise if there is another way to put contours and property boundaries onto google earth pro. Or another system that will do the same.
Also have fitted trackimo to p4p incase of fly away or similar incident.

@Geoff44 - RE contours and GE: Try looking on hiking / backpacking websites; there was a post on PhantomPilots that mentioned GaiaGPS.com or another site that I don't recall; however, there are hiking sites where contours and GE are mentioned; even have useful tools.

Please post back if you find results.

 

[bsartist]

Regarding this comment:

• - It only does RTG at the WP’s and NOT between WP’s - be aware of obstacles between WPs

This is a sometimes overlooked fact and the key takeaway from this is that it’s imperative to place many waypoints when planning an AGL mission over uneven terrain to provide as many GL sampling points as possible. Lest a high point creep up in between waypoints that Litchi won’t account for.

 

[jimlips]

Hi,
I have been loving using Litchi with my Phantom 4 Advanced and my missions around the house have been going well. I just took it out on the farm (what I bought it for) and sent it on a hilly mission that I had carefully planned and double checked with Google Earth.

It seems it disconnected and crashed pretty shortly thereafter. It seemed too low just before it disappeared.

I'm thinking either Google Earth altitudes are out by 10m or so OR it goes to each waypoint and then changes altitude (and I had assumed a straight line between the two). Can anybody help? This would help me decide where to search.

I will go and hunt for it in the gorse in the morning. I had so much work planned for it and it was going so well!

Sorry it has been so long, but I just saw your post. Check out this excellent video - it taught me a lot on how to check your heights using Google Earth, and the proper settings of the same to get a predictable result using Litchi:

 

[mjlp]

65' AGL?? Most trees are 80' and some pines can reach 110-120' I always fly at a minimum of 150' and even then the trees appear very close.

Good advice..

 

[RodPad]

@mjlp,

Anything new on your search?

Rod