Hello everybody,

I'm new here.
I have recently purchased a DJI Mavic Mini. I'm practising with it, and hopefully I will be able to master it properly soon.
My main interest, as a hobby, would be the aerial survey of old  buildings, but I would need a compass reading shown on the display  during the flight or the hovering above the buildings. I mean that I  would like to know where the North is when I take an aerial photo of a  place. This would be very important to me.

The drone has an internal compass, it has to be calibrated before a flight, so the drone does know where the North is.
Would it be possible to have that bit of info live on the display during a flight?
If no, would it be possible to ask the developement team to add this  feature in a future release of the DJI Fly App? How could I do that?

Any suggestion is more than welcome.


Thanks so much in advance  

Are you looking to have the photo direction embedded in the photo properties or just want a N,S,E,W, marker on the controller screen?

To be honest if you are taking photos and video of a specific place I would go onto Google Maps ahead of time and you can determine what side of the building North would be and then once onsite you can easily keep track of the other locations.

Cavu Films Posted at 8-24 12:19
Are you looking to have the photo direction embedded in the photo properties or just want a N,S,E,W, marker on the controller screen?

To be honest if you are taking photos and video of a specific place I would go onto Google Maps ahead of time and you can determine what side of the building North would be and then once onsite you can easily keep track of the other locations.

Hi @Cavu Films,
Thanks for the reply.

Going on Google Maps beforehand to know where the north is, honestly is a bit strange.
Why should I check it beforehand when the drone knows exactly where the north is?
And what if I am taking a photo of something that I hadn't planned to survey?

I do such surveys during my trips abroad, I wouldn't like to leave home with tens of photos of places that I want to visit.

The compass value imposed on the image would be great. If I am flying the drone above a building, I could use some yaw to align the drone to zero degrees north before shooting a picture, and I would know that the top of the photo is north sharp.

I can't believe that such a device can't tell me something that it does know.
It seems, though, that other Apps or drones do (or don't do) just the same.

My opinion is that these flying devices have been conceived more for playing and keeping people amused, rather than allowing people to use them for useful tasks.

Use the compass app in your phone

A J Posted at 8-25 13:57
Use the compass app in your phone

Hi @A J,
Thanks for your reply.

Would you please explain to me how I could interface the Compass App of my phone with the photo shown in DJI App?

My need is:
I'm hovering over a building (namely an old castle or other similar buildings), the camera of the drone pointing to the ground, vertically above the building, so that I see the building in plan.
The compass reading on the App (if ever available) would tell me where the head of my Mini is pointing. With a bit of yaw I would spin the Mini until the compass reading is 0°, so the top of the image is north. Now I would take a photo of the building from high above.
This is what I would need for my use.

I had this kind of expectation when I purchased the drone.

Thanks!

IrishStones Posted at 8-26 04:36
Hi @A J,
Thanks for your reply.

Alternatively go into the map screen and align the heading to North - that will give you a clearer view in which direction to North the nose of the drone is facing.

IrishStones Posted at 8-25 05:17
Hi @Cavu Films,
Thanks for the reply.

I understand you totally but for the amount of programming needed for that function to be added to the image file obviously got removed from the software development side of things. I am sure it was talked about but the need probably wasn't there. When I am doing photo shoots I have a pretty good sense of my directions so when I label an image for someone I can tell them which direction is N,S,E,W. No one has ever asked me to label something with 0 degrees North.

Hopefully you can find a solution that fits your needs.

A J Posted at 8-26 04:54
Alternatively go into the map screen and align the heading to North - that will give you a clearer view in which direction to North the nose of the drone is facing.

Hi @A J,
thanks for your suggestion.

I made a few experiments, I flew my drone up above my home and took several vertical photos using the map screen and the arrow pointing North.
Then I compared those photos with the Google photos and I found a ±3° difference, the arrow doesn't have a great resolution. Not bad, but I would have liked a higher precision. Maybe I just need to practice it more.

The downside of this technique is that the smartphone connected to the controller needs a web connection too to show the map, or I only got an arrow on a white field.
I purchased a second hand phone to be used with Mini only, so this phone has no SIM card.
The reason for this second phone was that I was positive that my old first phone was responsible for the controller's battery drainage.

Anyway, your suggestion might be a starting point for sure, thanks!

Cavu Films Posted at 8-26 10:14
I understand you totally but for the amount of programming needed for that function to be added to the image file obviously got removed from the software development side of things. I am sure it was talked about but the need probably wasn't there. When I am doing photo shoots I have a pretty good sense of my directions so when I label an image for someone I can tell them which direction is N,S,E,W. No one has ever asked me to label something with 0 degrees North.

Hopefully you can find a solution that fits your needs.

Hi @Cavu Films,

That's a good point.
Yes, I have a good sense of direction too, but knowing where the north is (roughly), isn't the same thing of knowing where the north exactly is. For what my needs are, a few degrees might make the difference.
I followed the A J's advice in the previous post, and I got an accuracy of ±3°, which isn't bad, but it could be better.

Probably it is like you say, the data flow was to heavy to be handled and the request for that bit of info was low.
I'm no expert in the programming field, but the amount of programming should be more or less quite the same of the one used to show the altitude and distance.

It wouldn't be bad if there was an email address to which send suggestions for future releases of the App.

IrishStones Posted at 8-28 05:35
Hi @A J,
thanks for your suggestion.

You're welcome - hope you find the best solution for your needs.

Hi!

If you're on a Mac, you should be able to open a terminal, go to a directory with your photos, and run this command:

egrep -a -e 'FlightYaw' *

Here's what I get in my directory containing my Mavic Mini photos:

DJI_0066.jpg:   drone-dji:FlightYawDegree="+144.60"
DJI_0070.jpg:   drone-dji:FlightYawDegree="+143.40"
DJI_0074.jpg:   drone-dji:FlightYawDegree="-16.10"
DJI_0076.jpg:   drone-dji:FlightYawDegree="+71.70"
DJI_0080.jpg:   drone-dji:FlightYawDegree="-157.40"

I do not know if this is true north or compass north, but you can certainly correct based on the location of your shots.  Also, these yaw values seem to correspond to where the drone was looking.

If you have a Windows machine, I don't know how you'd extract it, but you should be able to do it.  This is simply text data embedded in the binary jpeg.  I hope this helps!

mathogre Posted at 11-23 07:03
Hi!

If you're on a Mac, you should be able to open a terminal, go to a directory with your photos, and run this command:

Hi Mathogre,
Thanks for your reply.

I use Windows, but if a Mac system is able to extract the data from the metadata embedded in the jpeg file, some other image browser or editor might be able to read it too.

What is wrong with this, though, is that I will know the 'yaw degree' info only AFTER taking the photo, when I download it to the pc, not WHILE I am taking the photo, so that I might align the Mavic Mini in order to have the north on top of the photo.

Thanks for your suggestion, anyway, I will try to investigate this, probably there is more in the metadata than we can think.

Hi IrishStones!

I understand now.  Sorry!  You were clear about what you wanted and needed.

mathogre Posted at 11-23 14:02
Hi IrishStones!

I understand now.  Sorry!  You were clear about what you wanted and needed.

Hi Mathogre,

No need to be sorry. Your contribute has been helpful nonetheless, I and others have learned something that we didn't know.
Thank you.

As for my needs, I hope that DJI will come out with a new release of the App with this bit of info made available on the display. I hope it will be a good new release, unlike the last one who gave us lots of problems, I had to downgrade the App to several releases ago.

mathogre Posted at 11-23 07:03
Hi!

If you're on a Mac, you should be able to open a terminal, go to a directory with your photos, and run this command:

Wow, while reading this post I found a website

https://compress-or-die.com/analyze-process

which does, after the fact, extraction of all the info encoded into the MA2 (and other jpegs) images, to include:

About         DJI Meta Data
ModifyDate         1970-01-01 00:00:00
CreateDate         1970-01-01 00:00:00
Make         DJI
Model         Test_Pro
Format         image/jpg
GPSLatitude         26.061201 N
GPSLongitude         80.442421 W
AbsoluteAltitude         +83.30
RelativeAltitude         +83.30
GimbalRollDegree         +0.00
GimbalYawDegree         -68
GimbalPitchDegree         -14.6
FlightRollDegree         -0.4
FlightYawDegree         -68.8
FlightPitchDegree         +0.40
CamReverse         0
GimbalReverse         0

Based on what others have posted, the GimbalYawDegree         -68 would be 360 + GYD = 292 degs on the compass.