Litchi chit-chat ... What's Litchi? Should I use Litchi?

[B0M0A0K]

To all you Litchi experts (that means anyone with more than my 1 day experience ). Is that right that you still can’t fly a waypoint mission and include an orbit as part of the “action” to take at a POI?

Caveat: I am going to try hard to stop comparing Litchi to Maven.

What the heck, Maven was able to do this out of the box as an action performed at a specific POI?

[OzoneVibe]

@B0M0A0K

Is that right that you still can’t fly a waypoint mission and include an orbit as part of the “action” to take at a POI?

Correct.

[B0M0A0K]

OK, that seems a shame. I see that others get past this by either plotting a circle via multiple waypoints, or using Google Earth and a plugin to create and then export the orbit.

Is this still the most common way to achieve this?

[OzoneVibe]

@B0M0A0K

I need a little help understanding the “Above Ground” function and whether I should be using it by default, or why I might not want to use it.

By default? That depends - and it almost too difficult to explain without pages. Best left to learning by experience, really.

@B0M0A0K

It seems to me (and that doesn’t mean much), that if this function is turned off then Litchi will base the drone’s altitude off the altitude at the first Waypoint, in effect treating the flight path as a flat uniform surface and calculating it’s (the drone’s) height off that measurement.

Correct.

@B0M0A0K

My understanding of the “Above Ground” option is that this is based off some map data (maybe Google Earth Topographical) data and vary the height you set to always be “x” feet above the ground based on the topographical data. This means that the mission will see the ground as an undulating surface and calculate altitude accordingly.

Also correct - but beware …

• The ground height data is only available to Mission Hub (web UI) and the app whilst planning a mission
• once the mission is created by reference to ground heights - the resulting mission behaves to differently to one created without
• it assumes that you actually take off from below WP1
• for each WP, it calculates the relative land height and adds that difference to the height you set above that WP.
• there is no calculation of changes to ground height between WPs … ie. if the ground rises between WPs, it doesn’t know about that. (Suggest you look in posts above re VLM (Virtual Litchi Mission) that at least shows a flight profile and ground profile.)

[OzoneVibe]

@B0M0A0K

Is this still the most common way to achieve this?

It’s quite easy to plot an orbit with just a few WPs within a mission using curves.

[macspite]

Pretty much.

I live by the sea so often don’t have the above ground function switched on. Any heights you put into the mission in that instance are relative to the take off point.

The above ground function does use Google Earth information. I have used it and it seems to work fairly well. I am suspicious - or carefu l- of using it though as i have no idea how far apart Google Earth topographical heights are or, if you set height above ground at 20 metres, it will fly relative to the ground at that height until it meets a 25 metre tall tree.

also, Google Maps show the layout of an area as it was sometime in the past. There are times when a large or tall structure has been erected but the satellite image not yet updated …

[B0M0A0K]

OK, I will give this a go and see how I get on. Thanks!

[OzoneVibe]

With ground heights - you can also have the POI at a height above ground … the top of a tower, for instance - and the camera will be pointed at that point, rather than the ground at that point.

[B0M0A0K]

Yeah, they don’t seem to update GE or Google Maps very often. I was planning a Waypoint mission yesterday and neither showed how the land in a nearby field has been dug up as park of an offshore wind farm cabling project. They’ve been at that for three years now.

[B0M0A0K]

Happy to report that I managed to get out this morning to try my new Android tablet and the three test missions I had planned (Through Mission Hub). All went according to plan and my AIR2S behaved the way I wanted it to.

As a safety measure I had turned on most of the speech settings in Litchi, so they were quite “chatty” test flights.

Also as a precaution I had each mission start with a delay of 5-10 seconds over the home position before turning on the video and proceeding with the flight. Gotta say, I am very much enjoying the Mission Hub site and have been following a planning suggestion to load each flight into Google Earth and double-checking the flight path.

Early days, and there’s so much to learn. Baby steps me thinks

[OzoneVibe]

Glad to hear progress and success are being made.

@B0M0A0K

have been following a planning suggestion to load each flight into Google Earth and double-checking the flight path.

Best done using VLM, as above. I rarely fly a mission without using it to double check ground clearance and camera angles.
VLM has a Mission Hub interface built in (with a couple of extra functions added), so there’s nothing new to learn in the planning stage.
Once complete you just click the globe icon and it loads the mission into Google Earth for you.

[B0M0A0K]

I need to look again at VLM to be honest, I downloaded it and took a look, but I think I must have misunderstood its purpose. I went in expecting to be able to plan and upload, but also fly the mission virtually. I guess that’s what comes from not reading the feckin instructions.

[OzoneVibe]

@B0M0A0K

expecting to be able to plan and upload

In that respect it’s no different to Mission Hub

@B0M0A0K

but also fly the mission virtually.

This you can most definitely do - and it’s its main purpose.
In Google Earth, you can even create a video of the planned mission … eg …Flying in London! 😉

[B0M0A0K]

@OzoneVibe

eg …Flying in London!

Point taken, I will attempt to engage my brain and go learn

[OzoneVibe]

There is a learning process to it all, for sure.

[B0M0A0K]

So this is exactly why I get confused about the “Above Ground” setting. This Litchi Mission was planned with the “Above Ground” feature off. For all the cautions given previously I had THOUGHT that leaving that tick box unchecked would be my default setting. But the “altitude plot” has had me rethinking the whole thing again.

I may try flying the mission as it is now, with the “above ground” setting set to off, and then re-fly the same mission with that feature turned on, so I can compare the same information.

But as stated previously, it would be a mistake to blindly trust the topological data.

[OzoneVibe]

VLM will use the ground height data to plot that at the bottom of the screen you grabbed. But the WPs look like they have been set as specific heights (relative to take-off) OK - or they would have two figures next to each of them … the height above ground AND the height above take-off,

[B0M0A0K]

I assume that this is a correct response from the logs because I was not inputting control changes, it was all being done by Litchi?

[B0M0A0K]

Interesting. There’s alot more here to try out and investigate.

[OzoneVibe]

Litchi flights should appear as normal in AirData … as per …

… you’ll see that it says “SDK App” in bottom left.