Orbit mode centerpoint

The Litchi app can do an orbit with a minimum 15’ (3M) radius. The DJI Fly app can’t do a circle that small.

BUT, the centerpoint of the orbit when marked on the map (using a table iPad) isn’t exactly the actual center. For example, an orbit around a flagpole or church spire may not have the object in the center (almost hit what I thought was the centerpoint structure).

Am I not using the marker on the map properly? Is this just an approximate position based on GPS accuracy limits? Can the map be zoomed in any closer?

Example video: Litchi drone "orbit" test flight - YouTube

I experienced the same problems when testing the orbit mode. I set up 10m altitude and 5 m radius. The drone started to orbit on about 4 m and was going outside of the 5m radius toward the tree. I was able manually to lift it to 10m altitude. The drone behaved neurotic during the whole 2 minute flight. The interface of the app is confusing including the lack of the clear start button, especially that the settings button was not active while initially clicking on it many times. I am ditching Litchi. A cheep lesson never to buy a third party app.

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Watched your video. That was really close. With taller structures, Google Maps will show a parallax effect where the top of a tower or building is offset from its actual location (as you would expect in a 3-D view). Selecting that shifted top of a tower as your centerpoint will result in a shifted orbit.

Without seeing the Google Maps view of your location, that would be my best guess as to what is going on.

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Hi @wesbarris,
You may be correct. The Google map looks “flat” on-screen, but the world isn’t that way (or is it?).

Litchi can do very tight orbits (15’ radius) while DJIFly has a larger minimum orbit. I’m trying to shoot some architectural features (e.g. church steeples) so want nice “tight” shots. I will keep experimenting with GPS offset and variability and report back here (pending a crash)
Doug

I would start out with a larger radius. As you refine your centerpoint you can reduce your radius until you achieve a suitable orbit.

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Thanks for these replies.

I agree that when you use “orbit” mode within the Litchi app that you need to watch (or change) the centerpoint slightly due to Earth view parallax effect on Google maps. When North of the Equator, the images are tilted slightly upwards.

Here is a GPS comparison of the centerpoint of the latest video I posted here:

Litchi app (on an iPad):
41.463129
-81.540188

Google maps (on same iPad)
41.463.1286
-81.5401897

Google maps (on large screen PC)
41.463129876285635
-81.5401884374914

And what do you get if fly over the center with the the gimble set at -90, by far the best way of finding the center for an orbit

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Hi Martin,
agreed. I’m just sharing data for others who fly very small orbits.

So, you fly a manual mission over the center of your planned radius. Gimbal 90 degrres down. Make a note of that location. Then establish that as center of new orbit, set altititude to be 10’-20’ lower, set radius to minimum 15’ and let it go!

BTW, here’s something I just read about GPS accuracy:
“… it’s always safe to figure that the sixth decimal place in one decimal degree has 111,111/10^6 = about 1/9 meter = about 4 inches of precision.…”

Basically yes, or if I’m using Dronelink, it has it as an “On the Fly” mission wizard where it asks you to do just that, marking each stage as you go, plus you can set the speed the drone flies at, then once flown you can save it for future use