Greetings DJI

While shooting jpeg or DNG results in the photo is being tagged with a funky GPS Altitude. Here's what exiftools says (which matches photoscan):


GPS Altitude                    : 115161993.7 m Above Sea Level


thanks!

I thought it was limited to 500m  

Hi there, just to verify, does the issue appear in every picture? May I know what's the current firmware and APP version? Please kindly upload some original photos in the SD card to Dropbox and share us the link, we'd like to check the exact status, thanks in advance!

DJI Susan Posted at 2018-8-28 00:38
Hi there, just to verify, does the issue appear in every picture? May I know what's the current firmware and APP version? Please kindly upload some original photos in the SD card to Dropbox and share us the link, we'd like to check the exact status, thanks in advance!

Yes current firmware, upgraded yesterday after receiving the bird. Current ios app. Yes, all photos.

https://www.dropbox.com/sh/ifr67 ... ef1ayS6P3ght3a?dl=0

folks don't use these photos for comparison, some are out of focus (pilot error).

Also the absolute altitude seems wrong as well. Here I was flying about 97 meters above the ground, probably 270 meters MSL. The Relative seems right, but not the Absolute.

Absolute Altitude               : +1.20
Relative Altitude               : +97.80

My MP DNGs look accurate for altitude (at least as accurate as GPS altitude can be, which isnt very!).
Does the absolute change at all in the images or is it constant on them all?

gnirtS Posted at 2018-8-28 03:53
My MP DNGs look accurate for altitude (at least as accurate as GPS altitude can be, which isnt very!).
Does the absolute change at all in the images or is it constant on them all?

Absolute is 1.2 in every photo.

Interestingly, my MP1 ones are accurate BUT i tried the M2P sample DNGs from TomsTechTime and a few others and all are showing what you had, a stuck absolute and total altitude in hundreds of miles...

Edit:- Tested even more, all show the same.  All the M2P images appear to have broken EXIF altitude.

djiuser_6Q57jczySsAE Posted at 2018-8-28 03:34
Yes current firmware, upgraded yesterday after receiving the bird. Current ios app. Yes, all photos.

https://www.dropbox.com/sh/ifr67 ... ef1ayS6P3ght3a?dl=0

Also the absolute altitude seems wrong as well. Here I was flying about 97 meters above the ground, probably 270 meters MSL. The Relative seems right, but not the Absolute.

That's completely normal.
GPS is very, very bad for altitude (which is why your Mavic uses a barometer for flight altitude).
It's common for GPS altitude to be +/- 200 feet or more.

Labroides Posted at 2018-8-28 05:34
Also the absolute altitude seems wrong as well. Here I was flying about 97 meters above the ground, probably 270 meters MSL. The Relative seems right, but not the Absolute.

That's completely normal.

These are out by 71,000 MILES.....

gnirtS Posted at 2018-8-28 05:41
These are out by 71,000 MILES.....

That's obviously a glitch and it would be unusual if he sees that every flight.

I was commenting on the numbers shown in post #4.

Labroides Posted at 2018-8-28 05:34
Also the absolute altitude seems wrong as well. Here I was flying about 97 meters above the ground, probably 270 meters MSL. The Relative seems right, but not the Absolute.

That's completely normal.

The Relative Altitude of 97 meters is correct, and it's derived from the MP2's barometer. The Absolute altitude is broken (stuck at 1.2 meters), and it's also derived from the barometer. Both have nothing to do with the GPS.

The GPS altitude is off by greater than the diameter of the earth, so I call that broken. My experience with other DJI products is that the GPS altitude is typically within 5-6 meters of the ellipsoid height.

Labroides Posted at 2018-8-28 05:57
That's obviously a glitch and it would be unusual if he sees that every flight.

I was commenting on the numbers shown in post #4.

For fun, I flew the drone this morning, same exact problem.

djiuser_6Q57jczySsAE Posted at 2018-8-28 05:58
The Relative Altitude of 97 meters is correct, and it's derived from the MP2's barometer. The Absolute altitude is broken (stuck at 1.2 meters), and it's also derived from the barometer. Both have nothing to do with the GPS.

The GPS altitude is off by greater than the diameter of the earth, so I call that broken. My experience with other DJI products is that the GPS altitude is typically within 5-6 meters of the ellipsoid height.

The Absolute altitude is broken (stuck at 1.2 meters), and it's also derived from the barometer. Both have nothing to do with the GPS.
Actually, absolute altitude is derived from GPS and as I said, GPS is woefully inaccurate for altitude, commonly swinging +/- 200 feet and more.

I'm not sure where the big number is coming from but if you are getting something called Absolute altitude, that is shown in Exif data as GPS altitude.

Labroides Posted at 2018-8-28 05:57
That's obviously a glitch and it would be unusual if he sees that every flight.

I was commenting on the numbers shown in post #4.

Ive checked the sample DNGs online and they all show the same 72,000 mile issue.

That's one hell of a removed height restriction - its 1/4 of the way to the moon!

gnirtS Posted at 2018-8-28 04:00
Interestingly, my MP1 ones are accurate BUT i tried the M2P sample DNGs from TomsTechTime and a few others and all are showing what you had, a stuck absolute and total altitude in hundreds of miles...

Edit:- Tested even more, all show the same.  All the M2P images appear to have broken EXIF altitude.

Yea, I'm going to call this a verified bug. I can work around it, but it's extra work.

Labroides Posted at 2018-8-28 06:06
The Absolute altitude is broken (stuck at 1.2 meters), and it's also derived from the barometer. Both have nothing to do with the GPS.
Actually, absolute altitude is derived from GPS and as I said, GPS is woefully inaccurate for altitude, commonly swinging +/- 200 feet and more.

I stand corrected. The Absolute altitude does appear to be GPS altitude in my P4P images. It's also labeled above sea level, which I find a bit hard to believe. I wouldn't waste time putting a global GEOID table in the drone.

I suspect they just assume the earth is totally round surely.  GPS altitude is generally a mess on consumer devices even WITH a GEOID table.

djiuser_6Q57jczySsAE Posted at 2018-8-28 03:34
Yes current firmware, upgraded yesterday after receiving the bird. Current ios app. Yes, all photos.

https://www.dropbox.com/sh/ifr67 ... ef1ayS6P3ght3a?dl=0

Received with thanks! I'll forward to our engineers to check.

Labroides Posted at 2018-8-28 05:34
Also the absolute altitude seems wrong as well. Here I was flying about 97 meters above the ground, probably 270 meters MSL. The Relative seems right, but not the Absolute.

That's completely normal.

A baro has to be calibrated to give an absolute height (air pressure varies by height and weather).
Btw two days ago in the Alps when taking off from the exact same spot my Spark‘s MTA was spot-on (1681m) whereas my MA‘s MTA was 100m off (1582m).

Klaus W. Posted at 2018-9-7 01:07
A baro has to be calibrated to give an absolute height (air pressure varies by height and weather).
Btw two days ago in the Alps when taking off from the exact same spot my Spark‘s MTA was spot-on (1681m) whereas my MA‘s MTA was 100m off (1582m).

A baro has to be calibrated to give an absolute height (air pressure varies by height and weather).
Yes it does - for an airplane that needs to know absolute height.
But the drone's barometer is only used to give relative height.

Btw two days ago in the Alps when taking off from the exact same spot my Spark‘s MTA was spot-on (1681m) whereas my MA‘s MTA was 100m off (1582m).
That's quite normal.
GPS gives very inaccurate altitude.
It swings over short time periods and two GPS units side-by-side often show different numbers.

Update: Hi there, I just got an update from our engineers that GPS altitude issue will be fixed in the next firmware update. Thanks so much for your patience and support!

DJI Susan Posted at 2018-9-8 01:55
Update: Hi there, I just got an update from our engineers that GPS altitude issue will be fixed in the next firmware update. Thanks so much for your patience and support!

Thanks for the update. Looking forward to the new firmware.

djiuser_6Q57jczySsAE Posted at 2018-9-8 03:19
Thanks for the update. Looking forward to the new firmware.

We'll release on our website as soon as the new firmware is ready.

DJI Susan Posted at 2018-9-10 02:51
We'll release on our website as soon as the new firmware is ready.

Any update on this? I use my MP2 for mapping and without the correct altitude the drone is  useless.

CarlitosDiaz Posted at 2018-9-15 20:16
Any update on this? I use my MP2 for mapping and without the correct altitude the drone is  useless.

Sorry for keeping you waiting. Our engineers are working on this and we'll release on our website as soon as it is ready. We'll keep an eye on the status as well. Thanks for your support and patience.

I have seen this as well.  It seems like 2 problems.  The flight record altitude log seems reasonable but offset when compared to a topographic map and reading from my phone GPS.

Flight   Record(m)	Photo Exif Altitude(m)	Estimated on Topography Map(m)	Iphone (m)
2504.8	118719641.6	2610	2606.6
121.1	115077717.9	85	85.7

Have seen this in other Mavic 2 images... states below sea level as well

I have the same issue

The problem is in firmware ... as I see mine photos as with same lest say "not so correct" altitude ... BUT  EXIFT  Altitude minus ~117556m will be delivered approximately correct altitude MSL. Based on 1000+ photos with geo corect info for points of photos

No news on the fix for this?

Pix4D software seems to be having issues processing MAVIC 2 drone data and they imply it is related to this altitude issue.  Below is an image of the result from pix4D processing where the blue is where the software says we droned and the red is where we actually droned...a difference of about 1.6 mile.   I know it's possible to manually adjust the file altitude geotags....is there a specific amount or ratio to adjust them by?

Glitchy Posted at 2018-9-25 10:45
Pix4D software seems to be having issues processing MAVIC 2 drone data and they imply it is related to this altitude issue.  Below is an image of the result from pix4D processing where the blue is where the software says we droned and the red is where we actually droned...a difference of about 1.6 mile.   I know it's possible to manually adjust the file altitude geotags....is there a specific amount or ratio to adjust them by?

[view_image]

A few posts back, someone suggests "EXIFT  Altitude minus ~117556m" is roughly correct. My suggestion is to use this method to fix the altitude of the first photo, then use the relative altitude tag to adjust the others. The GPS altitude provides an absolute value (e.g. MSL or height above ellipse, not sure), but it's not very accurate. The barometer-based relative altitude is much more accurate among the photos, which is way more important for photogrammetry.

So just to clarify...the latitude and longitude from the EXIF data in the image files IS correct.  It's only the altitude that is way off as we don't normally fly drones in outer space or inside the crust of the earth.

Glitchy Posted at 2018-9-25 13:02
So just to clarify...the latitude and longitude from the EXIF data in the image files IS correct.  It's only the altitude that is way off as we don't normally fly drones in outer space or inside the crust of the earth.

Yes, the lat and long are correct.

Just checking...

It seems to be fixed with the new update!

Looks like it didn’t fix it

CarlitosDiaz Posted at 2018-10-12 16:10
Looks like it didn’t fix it

It appears to have fixed it for me.

GPS Altitude                    : 210.6 m Above Sea Level

This is the GPS information of a picture taken on top of a table.

MSL = AGLish