Phantom 4 Pro Error "The Waypoint Distance is Too Close"

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Jaycarter
Posts: 10
Joined: Tue Dec 18, 2018 11:19 am

Phantom 4 Pro Error "The Waypoint Distance is Too Close"

Post by Jaycarter » Sun Mar 24, 2019 11:31 pm

Using DJI Phantom 4 Pro with Drone Harmony Plus and when setting up a manual mission using photos to set up a waypoint for smooth video I am receiving the error "The Waypoint Distance is Too Close"

Any clue?

Martin
Posts: 199
Joined: Wed Mar 28, 2018 4:47 pm

Re: Phantom 4 Pro Error "The Waypoint Distance is Too Close"

Post by Martin » Mon Mar 25, 2019 7:44 am

Jaycarter wrote:
Sun Mar 24, 2019 11:31 pm
Using DJI Phantom 4 Pro with Drone Harmony Plus and when setting up a manual mission using photos to set up a waypoint for smooth video I am receiving the error "The Waypoint Distance is Too Close"

Any clue?
Hello Jaycarter,

Yes, DJI imposes a minimum and a maximum distance between two consecutive waypoints. The error you see originates from DJI:
https://developer.dji.com/api-reference ... ose_inline

Unfortunately, they do not clearly document what these limits are. At the moment Drone Harmony uses a minimum waypoint distance of 1.2m when generating automatic flight plans. From some development forum entries, people also claim that the DJI imposed minimum distance is 0.5m and the maximum distance is 2000m.

What we shall do to improve your user experience is to warn you about these limits appropriately when you are creating manually a mission. I created a new feature request documenting this here:
https://ideas.droneharmony.com/ideas/DHPLANNER-I-224

What you can do to make your mission work, is to
  1. make sure to have sufficient distance between two consecutive photo triggering points @manual mission recording.
  2. manually remove waypoints that are too close to each other. (In case our smoothing algorithm placed them too close, please let me know, as then we should also improve our smoothing algorithm to adhere to the minimum distance limit)
Best regards,
Martin

Jaycarter
Posts: 10
Joined: Tue Dec 18, 2018 11:19 am

Re: Phantom 4 Pro Error "The Waypoint Distance is Too Close"

Post by Jaycarter » Mon Apr 01, 2019 3:11 am

HI,
Yes, the smoothing by the app is placing the waypoints too close.
I posted a video here https://youtu.be/Whx98NkegEA
The only reason I purchased the app is for the video smoothing feature.
Can you cancel my subscription?

Martin
Posts: 199
Joined: Wed Mar 28, 2018 4:47 pm

Re: Phantom 4 Pro Error "The Waypoint Distance is Too Close"

Post by Martin » Mon Apr 01, 2019 7:13 am

Jaycarter wrote:
Mon Apr 01, 2019 3:11 am
HI,
Yes, the smoothing by the app is placing the waypoints too close.
I posted a video here https://youtu.be/Whx98NkegEA
The only reason I purchased the app is for the video smoothing feature.
Can you cancel my subscription?
Hello Jaycarter,
Thank you for the feedback and even providing the video.

Yes, the smoothing is placing the waypoints too close. Something that should not happen. We will search for the bug and fix it. We are sorry for the inconvenience and hope you will come back to us as a happy customer once the bug is fixed.

In the meantime:
You can cancel your subscription directly within the app. Menu -> Account & App -> Manage Account

I will keep you informed here, once we have the fix and we will also put a reference in the release notes of the corresponding update.

Best regards,
Martin

Jaycarter
Posts: 10
Joined: Tue Dec 18, 2018 11:19 am

Re: Phantom 4 Pro Error "The Waypoint Distance is Too Close"

Post by Jaycarter » Mon Apr 01, 2019 4:19 pm

Does this affect all models of DJI drones or just the Phantom 4 Pro?

Thank You

Martin
Posts: 199
Joined: Wed Mar 28, 2018 4:47 pm

Re: Phantom 4 Pro Error "The Waypoint Distance is Too Close"

Post by Martin » Mon Apr 01, 2019 4:30 pm

Jaycarter wrote:
Mon Apr 01, 2019 4:19 pm
Does this affect all models of DJI drones or just the Phantom 4 Pro?

Thank You
No, the code part for this is completely independent of the used hardware. We just tried really hard to recreate the error with several different recorded flights, creating all possible 'nasty' scenarios for the algorithm. But unfortunately, we could not reproduce the error you experienced.

We then did a deep code analysis of our smoothing algorithm parts, where we found two border cases that could with a low probability relate to your instance where the smoothing created too close waypoints. For these border cases, we adjusted the code so that the generated waypoints will adhere to the minimum distance as well. This code change will be part of the next update. But again, I can't guarantee you at this stage it will solve your instance.

It would help us a lot if you could send us your instance (Menu -> Import & Export -> Export State -> send to e-mail support@droneharmony.com). Maybe it gives us pointers on how we can recreate the instance in a way so that it also will fail for us here. Making debugging and thus fixing possible.

Best regards,
Martin

Jaycarter
Posts: 10
Joined: Tue Dec 18, 2018 11:19 am

Re: Phantom 4 Pro Error "The Waypoint Distance is Too Close"

Post by Jaycarter » Sun Apr 07, 2019 8:27 pm

Email sent today.
Hope you are able to resolve the issue. I have tried 4 tablets along with 3 different drones and the same results.

Thank You

Martin
Posts: 199
Joined: Wed Mar 28, 2018 4:47 pm

Re: Phantom 4 Pro Error "The Waypoint Distance is Too Close"

Post by Martin » Mon Apr 08, 2019 7:44 am

Jaycarter wrote:
Sun Apr 07, 2019 8:27 pm
Email sent today.
Hope you are able to resolve the issue. I have tried 4 tablets along with 3 different drones and the same results.

Thank You
Hi Jaycarter,

Thank you. I'm looking into your instance now.

Best,
Martin

Martin
Posts: 199
Joined: Wed Mar 28, 2018 4:47 pm

Re: Phantom 4 Pro Error "The Waypoint Distance is Too Close"

Post by Martin » Mon Apr 08, 2019 9:40 am

Jaycarter wrote:
Sun Apr 07, 2019 8:27 pm
Email sent today.
Hope you are able to resolve the issue. I have tried 4 tablets along with 3 different drones and the same results.

Thank You
Hi Jaycarter,

I looked at your mission:

I checked the waypoint distances with our own distance computation. The closest two waypoints (waypoint 1 to waypoint 2 at the beginning of your flight plan) are >=1.21 meters apart, which in theory should be enough for the DJI limit (we suspect it to be at 0.5m to 1 meter, but their documentation does not say).

https://github.com/dji-sdk/Mobile-SDK-iOS/issues/195

The problem here is, that DJI uses a different method for calculating the distances of two geo coordinates. Depending on their implementation the precision of the result can highly depend at which lat/long you are at. Unfortunately, DJI does not document how their distance computation is done:

https://stackoverflow.com/questions/513 ... calculated
https://developer.dji.com/iframe/mobile ... _TOO_CLOSE

Drone Harmony currently uses 1.2 meters as a lower waypoint distance limit in its mission validations. We hoped that this would provide enough slack to account for the undocumented (and maybe unprecise) internal distance calculation of DJI. But based on your instance it seems now that this was not enough.
Additionally, DJI does not offer to call their mission validation method before uploading the mission. So we only know that a mission is invalid according to DJI once we try to upload it to the drone. :roll:

For now, you can manually adjust the position of Waypoint 1 or Waypoint 2 in your flight plan (or even remove one of them). This will allow you to then fly your mission. We will likely increase our own lower waypoint distance limit or maybe even add it as a parameter in the global settings. Unless DJI reveals how they compute the distance or allows to call their validation method independently, that's probably the best we can do for now.

Best,
Martin

Martin
Posts: 199
Joined: Wed Mar 28, 2018 4:47 pm

Re: Phantom 4 Pro Error "The Waypoint Distance is Too Close"

Post by Martin » Mon Apr 08, 2019 2:12 pm

We did further tests and realized that the internal distance computation of DJI is really dependent on the latitude and longitude. For example, we can start a mission here in Zurich, Switzerland with 1.5 meters distance between two waypoints. The same mission type with the same distance can't be started at your location. By trial testing, we found that when increasing the distance at your place to around 1.9m to 2m suddenly the mission can be started.

What we plan to do now is the follows:
  1. If the DJI upload fails with this minimum waypoint distance error, we will offer a "cleanup procedure" that will gradually increase the distances of the waypoints (and/or remove some waypoints if necessary).
  2. Retry to upload that mission.

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