Need help understanding altitude numbers in LItchi waypoints

[vindibona1]

As I plan an upcoming mission in Litchi I need to understand exactly how high I am flying at every point, but I'm a little confused about the altitude reading on Litchi. Each waypoint has two readings, with one in parentheses, and one without. I want to make sure I understand what both numbers mean as I need to make sure I have enough height clearance for everything I'm flying past. Below is an image detailing the flight path and waypoints. Please note Waypoint 7. It's says "150" but then is followed by "(106)". In the waypoint settings you can see that the Altitude is set to 150 feet and the "above ground" tick box is checked. [Please note that the elevation from Google Earth is 654 ft (assume MSL?)] So if the Waypoint is set to fly at 150 ft above ground (?)... what does the "(106)" represent???? FWIW, this is Class D airspace and I've already applied and granted authorization (my first time doing that).

 

[Jeff A]

As I plan an upcoming mission in Litchi I need to understand exactly how high I am flying at every point, but I'm a little confused about the altitude reading on Litchi. Each waypoint has two readings, with one in parentheses, and one without. I want to make sure I understand what both numbers mean as I need to make sure I have enough height clearance for everything I'm flying past. Below is an image detailing the flight path and waypoints. Please note Waypoint 7. It's says "150" but then is followed by "(106)". In the waypoint settings you can see that the Altitude is set to 150 feet and the "above ground" tick box is checked. [Please note that the elevation from Google Earth is 654 ft (assume MSL?)] So if the Waypoint is set to fly at 150 ft above ground (?)... what does the "(106)" represent???? FWIW, this is Class D airspace and I've already applied and granted authorization (my first time doing that).

View attachment 111020

In your example, the drone is 150 feet above the ground AT THAT WAYPOINT and is 106 feet above the point where you took off.

 

[Camino Ken]

In your example, the drone is 150 feet above the ground AT THAT WAYPOINT and is 106 feet above the point where you took off.

Hey Jeff - you might have that slightly backward. The number in parenthesis is the attempt to calculate the height above ground. If you uncheck the “above ground” box, it goes away.

 

[vindibona1]

In your example, the drone is 150 feet above the ground AT THAT WAYPOINT and is 106 feet above the point where you took off.

Hey Jeff - you might have that slightly backward. The number in parenthesis is the attempt to calculate the height above ground. If you uncheck the “above ground” box, it goes away.

Hence my confusion.

 

[Jeff A]

Hence my confusion.

I don't think this conversation is over with!

 

[Camino Ken]

Hence my confusion.

What are you still confused about?

 

[slup]

Hey Jeff - you might have that slightly backward. The number in parenthesis is the attempt to calculate the height above ground. If you uncheck the “above ground” box, it goes away.

No, think @Effects have his thinking mostly correct ... the first number is the height you want the drone to be above ground (150ft) & the second (106ft) tells us that the ground elevation at that waypoint is 44ft lower than the first waypoint in the mission ... meaning that the height reading in Litchi during the execution of the mission will show 106ft at that waypoint ... = 150ft above ground. If the "Above ground" wasn't marked there, the AC would have been 194ft above ground.

Here below an example with 9 waypoints ... all set to 1m height. The mission goes uphill a small hill & I have marked "Above ground". During this mission the AC will be 1m above ground at every waypoint ... but at the last waypoint it's ascended in total to 24,3m above the first waypoint.

If I hadn't marked "Above ground" the AC had slammed into the ground just after the second waypoint.

 

[Jeff A]

No, think @Effects have his thinking mostly correct ... the first number is the height you want the drone to be above ground (150ft) & the second (106ft) tells us that the ground elevation at that waypoint is 44ft lower than the first waypoint in the mission ... meaning that the height reading in Litchi during the execution of the mission will show 106ft at that waypoint ... = 150ft above ground.

Here below an example with 9 waypoints ... all set to 1m height. The mission goes uphill a small hill & I have marked "Above ground". During this mission the AC will be 1m above ground at every waypoint ... but at the last waypoint it's ascended in total to 24,3m above the first waypoint.

If I hadn't marked "Above ground" the AC had slammed into the ground just after the second waypoint.

View attachment 111024

Thank you Sir!

 

[Camino Ken]

No, think @Effects have his thinking mostly correct ... the first number is the height you want the drone to be above ground (150ft) & the second (106ft) tells us that the ground elevation at that waypoint is 44ft lower than the first waypoint in the mission ... meaning that the height reading in Litchi during the execution of the mission will show 106ft at that waypoint ... = 150ft above ground. If the "Above ground" wasn't marked there, the AC would have been 194ft above ground.

Here below an example with 9 waypoints ... all set to 1m height. The mission goes uphill a small hill & I have marked "Above ground". During this mission the AC will be 1m above ground at every waypoint ... but at the last waypoint it's ascended in total to 24,3m above the first waypoint.

If I hadn't marked "Above ground" the AC had slammed into the ground just after the second waypoint.

View attachment 111024

I wholeheartedly respect your opinion but this disagrees with the Litchi manual.

Waypoint: The purple pointer with a number inside indicates a Waypoint, the small number is the altitude of the Waypoint above the takeoff point, if a second number is present in parentheses this indicates that the above ground level option is turned on this second number indicates the altitude above the Waypoint ground level.

i acknowledge that this was taken from what I believe is an an after market manual writer and not an official one. I guess it could be wrong but then why does the number in parentheses disappear when you uncheck the “above ground checkbox”?

 

[vindibona1]

I sent a note off to Litchi support, but they probably won't respond until tomorrow or even later.
As you can see I planned my mission so as not to fly over anything except trees. I can't imagine any tree being over 75 ft tall, but I may do a manual pre-mission flight to check, just to be sure.

 

[Camino Ken]

The manual info.


Unlocking the full potential of your DJI aircraft with Litchi

Software Manual for the Litchi flight control software and Flylitchi.com Mission Hub site.

by Don Wiley, Gold Wingnut Productions, LLC Revision date: 14 February 2020

 

[Jeff A]

The manual info.


Unlocking the full potential of your DJI aircraft with Litchi

Software Manual for the Litchi flight control software and Flylitchi.com Mission Hub site.

by Don Wiley, Gold Wingnut Productions, LLC Revision date: 14 February 2020

This page

 

[Camino Ken]

This page

I stand corrected and will eat the necessary amount a humble pie. Both are from the same source but yours is version 2a and mine is version 2. He must have corrected the manual.

 

[Jeff A]

I believe this will illustrate my point:

 

[Camino Ken]

I believe this will illustrate my point:

I agreed with you, no need to rub it in.?

 

[Camino Ken]

No, think @Effects have his thinking mostly correct ... the first number is the height you want the drone to be above ground (150ft) & the second (106ft) tells us that the ground elevation at that waypoint is 44ft lower than the first waypoint in the mission ... meaning that the height reading in Litchi during the execution of the mission will show 106ft at that waypoint ... = 150ft above ground. If the "Above ground" wasn't marked there, the AC would have been 194ft above ground.

Here below an example with 9 waypoints ... all set to 1m height. The mission goes uphill a small hill & I have marked "Above ground". During this mission the AC will be 1m above ground at every waypoint ... but at the last waypoint it's ascended in total to 24,3m above the first waypoint.

If I hadn't marked "Above ground" the AC had slammed into the ground just after the second waypoint.

View attachment 111024

Sorry for doubting you.

 

[slup]

I wholeheartedly respect your opinion but this disagrees with the Litchi manual.

Waypoint: The purple pointer with a number inside indicates a Waypoint, the small number is the altitude of the Waypoint above the takeoff point, if a second number is present in parentheses this indicates that the above ground level option is turned on this second number indicates the altitude above the Waypoint ground level.

i acknowledge that this was taken from what I believe is an an after market manual writer and not an official one. I guess it could be wrong but then why does the number in parentheses disappear when you uncheck the “above ground checkbox”?

Litchi states this in their web based user guide ... you find it here --> Help - Litchi (click on Mission Hub & scroll down)

 

[slup]

Sorry for doubting you.

No worries ... sometimes even I misunderstand thing's

 

[Camino Ken]

No worries ... sometimes even I misunderstand thing's

I misunderstand things as well, a bit more often that I like, but in this case it was an outdated 3 party information manual. You can see the excerpt above.

 

[Jeff A]

Sorry for doubting you.

I didn't see your post until after I posted the Mission.