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More test of Mavic 2 Pro image tags

I took photos at 5 feet elevation intervals from 5 feet to 100 feet.

My launch elevation (orthographic height from google earth) is 245 meters above MSL, also this matches my iphone's GPS elevation.

The images, both jpeg and DNG, contain three Altitude tags.

  • AbsoluteAltitude  - this is broken, as it is always set to 1.2
  • RelativeAltitude - this appears to be *uncorrected* barometric height above MSL.
  • GPSAltitude - this appears to the RelativeAltitude value truncated to a single digit beyond the decimal place (NOTE, it's not rounded, but truncated)



Values for the photo at 5 feet AGL:
AbsoluteAltitude = 1.2 (broken)
RelativeAltitude = 130.87 meters
GPSAltitude = 130.8 meters

my iphone is saying 160 meters elevation based on its uncorrected barometric sensor, while its GPS is sayin 245 meters, so it seems clear to me that the Mavic is reporting uncorrected barometric readings for GPS and Relative altitudes.

Ssw

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Terrain Aware doesn't change anything about how the tags are recorded. All it does is keep the aircraft a consistent distance from the ground. 

It looks like a bunch of your images have a 0.0 written in to the tags. That is basically telling our system that your camera didn't write the tags properly, which it didn't. 

We have made a workaround for the Mavic 2 Pro internally but it still can't have zeros written in there. From the data we have seen it should be writing values in there even though they are incorrect. Our workaround does not cover the case where 0.0 is written into the GPS derived tag. 

Zane

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Sorry to burst in on your conversation. I too, have issues with altitude tags on my Mavic 2Pro. I have managed to make 2 "orders" on MME, where I have received a good result image+3D model.

Over the past days where I have made +10 flights, I get errors about altitude missing on my photos upon upload.

It has been an issue since I used the Terrain Aware, for the first time. The two pictures that I have made here on MME was done without this function.

As I mentioned I have done +10 flights now, some with and some without the Terrain Aware switched on.

Upon uploading the images, I get an error with about 50% of the images, saying that the altitude is set to zero ? - see below.

What can cause this issue? - It's very frustrating having made all these flights for costumers without being able to deliver a result.

The strange thing is that there is no difference in the EXIF data on a picture that is accepted by the upload feature:

And a picture that has been rejected on the upload:

 

When looking at the EXIF from a picture of my first MME flight, where the end result was a great 3D model of a house. I can see that the Exif shows a hight, and has a reference hight above water. Please not that I did NOT use the Terrain Aware for this flight.

What can I have done wrong? - or is it some software issue?

FYI im using:

Apple iPad Air 2 with iOS 12.1

MapPilot version 2.9.2

 

Kind Regards

Simon

Simon Vammen 0 votes
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Simon: Please email us one of your images. It sounds like the tags have been modified by other software but we would like to check yours out to be sure. 

Here is what we have figured out on the Mavic Air and Mavic 2 tags so far: 

Changes were made to a previously functioning Mavic Air firmware that broke things. We think this happened around when the Mavic 2 was released. 
 
The Mavic Air has switched from a 2 byte number format for the tag data to a 4 byte format which is why it is messing up a ton of viewers and software. The EXIF standard document says it is 2 bytes. We realize why they did it, RTK data requires the ability to report higher levels of precision, but it is dumb how they did it. They went from providing 7 decimal points (inches of precision) to providing around 15, which equates to providing micrometers of precision in the air. Not useful or realistic. Maybe in 10 more years of technological advances but then the EXIF standard and all the viewers would likely be updated to reflect this. 
 
We suspect that the rest of the DJI cameras and aircraft will eventually use the same formats. 
 
Then, in addition to the issue on the Air, on the Mavic 2 they decided to report the relative altitude in the GPS tags again and then not report the GPS derived altitude at all in the XMP section. Currently, a value of 1.2 meters is reported in all images in the Absolute Altitude number in the XMP tags. For some reason it is reporting a negative number for the Relative Altitude number in the XMP at takeoff. This value is 0 (or close to it) on all other aircraft. 
 
The short story is that we have accommodated the new format in Maps Made Easy to the extent that we can. For the time being Mavic 2 models still have some pretty weird stuff going on. We have added a specific case for handling it, which we do NOT like doing, but support for the Mavic 2 should be OK now. 
 
Feel free to share this. 
Zane 0 votes
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Hi Zane,

Thanks for your fast reply!

I have uploaded some pictures to this dropbox link:

https://www.dropbox.com/sh/sro0o1v4vf99r78/AAAHqPZKIluZw0URIp1xePgja?dl=0 

 

DJI_0379.jpg - First flight where the 3D model came out perfect. Here the Terrain Aware was not used.

DJI_ 0641.jpg - Another flight, here the Terrain Aware was on for the first time, and picture failed upon upload to the site.

DJI_0714.jpg + DJI_0715.jpg - Ground and air photo of the most recent flight, that also was rejected upon import. Here the Terrain Aware was switched off.

 

Let me know if you need more files. Look forward to a result of your investigation as im very anxious for getting my Orto foto work done.. :/ 

Kind Regards

Simon

Mail: simon@vammen.eu

Simon Vammen 0 votes
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Hi Zane,

Thanks for clarifying the Terrain Aware function. But now that we can conclude that this probably is not the issue.

But the way the Mavic writes the tags. What can a possible solution be to this issue? - I myself are not able to do any programming in the software or the drone.

FYI, the pictures have NOT been through any editor, they have just been copied from the memory card to the computer and then uploaded.

But guess their must be other Mavic 2 Pro users out there having the same issues??

Kind Regards

Simon Vammen

Simon Vammen 0 votes
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Hi again Zane,

 

Just wondering if you have had a chance to look at the images I have uploaded to the dropbox link previously attached.

Have you reached a conclusion to the issue with the Mavic 2 Pro.

Kind Regards  Simon Vammen

Simon Vammen 0 votes
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Make sure you keep the firmware up to the latest released version. I don't know why some of the data sets have the tags and other don't. 

For some reason a bunch of your tags had 0.0 written into the altitude values which basically means they didn't get written at all. Maps Made Easy won't process data that doesn't have valid altitude tags. We do a few checks to make sure the altitude data was present and apparently this data set fails that test. 

We have addressed a number of things with how the Mavic 2 Pro tags are working but we can't fix the altitude data being totally missing. DJI has some work to do to get the Mavic 2 Pro to the same state as the other aircraft. The altitude tags on the M2P seem to vary between non-existant to not usable to fixable. This is likely due to firmware differences. Stay up to date and try again is all you can do at this point. 

 

Zane 0 votes
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Thanks Zane,

I'm absolutely sure that my software/firmware is always updated prior flight.

I have raised the issue towards DJI, and hope you as a company will do the same. I'm sure they will listen at bit more to you than us DJI costumers.

 

Simon Vammen 0 votes
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it is weird how your tags weren't consistent. That is something we haven't seen and aren't sure it is something we want to make a workaround for. 

Does it always create data sets that are not able to be uploaded or just sometimes?

Zane 0 votes
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11/27/2018
I updated my Mavic 2 Pro to the newest firmware 

  • Date: 2018.11.22
  • Aircraft Firmware: v01.00.02.00

I did a small mapping mission on Saturday Nov 24th and the map actually rendered on the correct location in the output on Google Earth.
My previous attempts with the older firmwares resulted in fragmented maps scattered randomly about on Google Maps overlay which were unusable.
The previous issues were a result of incorrect GeoTag data.
Has anyone else tested the latest firmware to confirm the GeoTags are now correct?

View my Sat Nov 24th map created from 62 Mavic 2 Pro images here: https://www.mapsmadeeasy.com/maps/public/d8fe2f0f4cc84a0fb10c9842fbab52b4

Brett Davis 0 votes