Incorrect EXIF GPS and Elevation

ST@AerialMetrics · Aug 30, 2018

Mavic 2 Pro flight and pictures excellent, but image EXIF data shows altitude was a bit over 115 million meters...which would be impressive if true. Lat/Lon also consistently off by about 3/4 mile. This matters when feeding pics into Pix4D photogrammetry software. Anyone else check their EXIF yet?

Update 3/8/2019: firmware long ago fixed the altitude problem, but the Lat/Lon error into Pix4D persists for Mavic 2 and M2E. Here's a link to a free tool that produces a corrected Lat/Lon EXIF import file for Pix4D. DJI Mavic 2 GPS correction for Pix4D | Aerial Metrics

Bunny Too · Aug 30, 2018

ST@AerialMetrics said:
Mavic 2 Pro flight and pictures excellent, but image EXIF data shows altitude was a bit over 115 million meters...which would be impressive if true. Lat/Lon also consistently off by about 3/4 mile. This matters when feeding pics into Pix4D photogrammetry software. Anyone else check their EXIF yet?

Howdy from Wyoming @ST@AerialMetrics, welcome to the community, plenty of fine folk and excellent information here. There are two other threads about this, I am sure it will be addressed in a firmware update.

physixtential · Nov 17, 2018

I can confirm that this issue still exists. No firmware fix. From what I have seen, DJI is the worst company anyone has ever heard of in terms of support.

physixtential · Nov 17, 2018

Bunny Too said:
Howdy from Wyoming @ST@AerialMetrics, welcome to the community, plenty of fine folk and excellent information here. There are two other threads about this, I am sure it will be addressed in a firmware update.

Please link to the other threads you mentioned.

queeg730 · Nov 19, 2018

Yes... I am getting very similar problems wiht EXIF Altituda data...... I can't use this machine for mapping with this data as it is!

In the attached images, I said that the Altitudes were consistent on ALL images, but this is NOT the case... I just did another test and they seem to be all over the place.... they seem to vary from day-to-day! If they were consistent, I could have manipulated the Exif data for the mapping software, but now I can't even do that!

What can we do to get DJI to fix this????? I would have thought it was a simple one .. I have also posted this same message on the thread "first-minor-issue-gps-exif-altitude.46307"

53-63-6f-74-74 · Nov 19, 2018

It's not difficult to batch-adjust your elevations, or any other data, in the exif info. I've done it before using imbatch freeware. It may or may not help in your particular case, but thought I would mention it as a potential tool.

Kildir · Dec 4, 2018

Hi all. Having had the same problem as everybody and knowing that DJI is not looking into it seriously, I have finally solved it, not without serious work on the image files themselves. Here is what happens and the solution I found:

1. DJI records Latitude and Longitudes at two different EXIF tags IDs (!): GPSLatitude/GPSLongitude and Latitude/Longitude. It looks that some of the GPS-prefixed EXIF tags are incorrect, I don't know why. However, the Latitude/Longitude tags are ok. The problem is that neither Pix4D or Photoscan read Latitude/Longitude, they use GPS-prefixed ones. These Latitude/Longitude tags are unusual, we don't see them normally, they seem to be in excess and are nor found by some EXIF tools. Exiftool from Phil Harvey can. It can list all tags with the exiftool -listg [filename] command.

2. The GPSAltitude tag is also buggy, sometimes it appears as a very large negative number. However, DJI uses two other tags for altitudes: RelativeAltitude and AbsoluteAltitude. The RelativeAltitude provides the barometric altitude difference between the actual position and the take-off position. AbsoluteAltitude is also bad, often equal to 1.2. There is no other place in the EXIF tags where we can find any reliable "above sea level" altitude so we need to know the take-off altitude and add it to the barometric relative altitude to get a reliable value.

Here is what shall be done. For each image, we extract values with the following command: exiftool -Latitude -Longitude -RelativeAltitude -csv [image name], add ground take-off altitude to the RelativeAltitude value and then re-insert those values into their correct locations with the following command: exiftool -GPSLatitude=value -GPSLongitude=value -GPSAltitude=value [image name].

Of course, doing it manually for each and every image in a dataset is too cumbersome. We can extract all values, put them in a .csv file and assign them to images afterwards with either Pix4D or Photoscan geolocation functions or create a program doing all this automatically using exiftool and just correct EXIF tags so that these software are happy just reading the images. I wrote a Python program that does that for a complete image directory. It is written in Python 3, called exifrepair.py and currently works well in Linux or Macos environments but it could perhaps work with minor modifications in a Windows environment, provided exiftool is installed and activates on the command prompt if called (exiftool is called with the "subprocess" command that I think works differently in Windows).

Here is a log printout after execution on a small dataset:

2018.12.04 14:15:00 ExifRepair V1.01: ------------------------------------
2018.12.04 14:15:00 ExifRepair V1.01: Start
2018.12.04 14:15:00 ExifRepair V1.01: Reading directory: Vol03
2018.12.04 14:15:00 ExifRepair V1.01: Found 7 files to repair for GPS positions
2018.12.04 14:15:00 ExifRepair V1.01: and add 104.0m to recorded relative altitudes
2018.12.04 14:15:00 ExifRepair V1.01: Repairing EXIF GPS tags for 20181016_10-38-51.jpg (1)
2018.12.04 14:15:01 ExifRepair V1.01: Repairing EXIF GPS tags for 20181016_10-39-00.jpg (2)
2018.12.04 14:15:01 ExifRepair V1.01: Repairing EXIF GPS tags for 20181016_10-39-11.jpg (3)
2018.12.04 14:15:02 ExifRepair V1.01: Repairing EXIF GPS tags for 20181016_10-39-19.jpg (4)
2018.12.04 14:15:02 ExifRepair V1.01: Repairing EXIF GPS tags for 20181016_10-39-27.jpg (5)
2018.12.04 14:15:03 ExifRepair V1.01: Repairing EXIF GPS tags for 20181016_10-39-34.jpg (6)
2018.12.04 14:15:03 ExifRepair V1.01: Repairing EXIF GPS tags for 20181016_10-39-41.jpg (7)
2018.12.04 14:15:04 ExifRepair V1.01: 7 images repaired for EXIF geotags
2018.12.04 14:15:04 ExifRepair V1.01: Stop
2018.12.04 14:15:04 ExifRepair V1.01: ------------------------------------

For those interested in either the Python script (for ideas or implementation) or processing service, please use the following link to send me an email by using my company's web site message page: Kildir Technologies

Sorry Kildir Technologies' web site is in French but the email sending page is pretty straightforward (Name, email, subject, message, captcha)

André

Paulo Lobo · Jan 20, 2019

Hi,

My dji mavic 2 pro, has no altitude in the EXIF fotos....
So i can not do mapping or 3dstatue....

Paulo Lobo

sar104 · Jan 20, 2019

Paulo Lobo said:
Hi,

My dji mavic 2 pro, has no altitude in the EXIF fotos....
So i can not do mapping or 3dstatue....

Paulo Lobo

They have the altitude data, both relative and absolute, in the XMP section of the EXIF data.

Paulo Lobo · Jan 21, 2019

Can you please explain more ??

Paulo Lobo · Jan 21, 2019

sar104 · Jan 21, 2019

You are only looking at a fraction of the data. Here are the full EXIF data from an M2P image file:

File Name : DJI_0184.DNG
File Size : 40 MB
File Modification Date/Time : 2018:12:29 12:49:22-07:00
File Access Date/Time : 2019:01:21 16:14:43-07:00
File Inode Change Date/Time : 2019:01:12 20:20:47-07:00
File Permissions : rwxrwxrwx
File Type : DNG
File Type Extension : dng
MIME Type : image/x-adobe-dng
Exif Byte Order : Little-endian (Intel, II)
Make : Hasselblad
Camera Model Name : L1D-20c
Orientation : Horizontal (normal)
Software : 10.00.08.17
Modify Date : 2018:12:29 12:49:22
Image Width : 5568
Image Height : 3648
Bits Per Sample : 16
Compression : Uncompressed
Photometric Interpretation : Color Filter Array
Strip Offsets : 821680
Samples Per Pixel : 1
Rows Per Strip : 3648
Strip Byte Counts : 40624128
Planar Configuration : Chunky
CFA Repeat Pattern Dim : 2 2
CFA Pattern 2 : 0 1 1 2
CFA Plane Color : Red,Green,Blue
CFA Layout : Rectangular
Black Level Repeat Dim : 2 2
Black Level : 4101 4108 4107 4105
White Level : 65535
Default Scale : 1 1
Default Crop Origin : 4 4
Default Crop Size : 5464 3640
Bayer Green Split : 0
Anti Alias Strength : 1
Best Quality Scale : 1
Active Area : 0 96 3648 5568
Opcode List 3 : (Binary data 12564 bytes, use -b option to extract)
Default User Crop : 0 0 1 1
Subfile Type : Reduced-resolution image
Preview Image Start : 71107
Preview Image Length : 750573
Y Cb Cr Coefficients : 0.299 0.587 0.114
Y Cb Cr Sub Sampling : YCbCr4:2:0 (2 2)
Y Cb Cr Positioning : Co-sited
Reference Black White : 0 255 128 255 128 255
About : DJI Meta Data
Format : image/dng
Latitude : +35.8938600
Longitude : -106.3887196
Absolute Altitude : +2849.93
Relative Altitude : +73.00
Gimbal Roll Degree : +0.00
Gimbal Yaw Degree : -116.00
Gimbal Pitch Degree : -26.00
Flight Roll Degree : -1.60
Flight Yaw Degree : -115.70
Flight Pitch Degree : +0.10
Cam Reverse : 0
Gimbal Reverse : 0
Self Data : DJI Self data
Version : 7.0
Has Settings : False
Has Crop : False
Already Applied : False
Exposure Time : 1/2500
F Number : 9.0
Exposure Program : Program AE
ISO : 400
Exif Version : 0230
Date/Time Original : 2018:12:29 12:49:22
Create Date : 2018:12:29 12:49:22
Exposure Compensation : -0.7
Max Aperture Value : 2.8
Metering Mode : Center-weighted average
Light Source : Daylight
Flash : No Flash
Focal Length : 10.3 mm
File Source : Digital Camera
Scene Type : Directly photographed
Exposure Mode : Auto
White Balance : Auto
Digital Zoom Ratio : 1
Focal Length In 35mm Format : 28 mm
Scene Capture Type : Standard
Gain Control : None
Contrast : Normal
Saturation : Normal
Sharpness : Normal
Serial Number : 0K8TF5W0020136
Lens Info : 28mm f/2.8-11
GPS Version ID : 2.3.0.0
GPS Latitude Ref : North
GPS Longitude Ref : West
GPS Altitude Ref : Above Sea Level
DNG Version : 1.4.0.0
DNG Backward Version : 1.3.0.0
Unique Camera Model : Hasselblad L1D-20c
Color Matrix 1 : 1.2385 -0.7159 -0.0657 -0.0982 1.0352 0.0721 0.0457 0.0241 0.7437
Color Matrix 2 : 0.731 -0.2746 -0.0646 -0.2991 1.0847 0.2469 0.0163 0.0585 0.6324
Analog Balance : 1 1 1
As Shot Neutral : 0.3413333333 1 0.6139088729
Baseline Exposure : 0
Baseline Noise : 1
Baseline Sharpness : 1
Linear Response Limit : 1
Camera Serial Number : 0K8TF5W0020136
Shadow Scale : 1
DNG Private Data : (Binary data 19829 bytes, use -b option to extract)
Calibration Illuminant 1 : Standard Light A
Calibration Illuminant 2 : D65
Profile Name : Embedded
Profile Hue Sat Map Dims : 18 6 1
Profile Hue Sat Map Data 1 : (Binary data 3408 bytes, use -b option to extract)
Profile Hue Sat Map Data 2 : (Binary data 3439 bytes, use -b option to extract)
Profile Embed Policy : Allow Copying
Noise Profile : 0.00025745 2.9e-07
Original Default Final Size : 0 0
Original Best Quality Size : 0 0
Original Default Crop Size : 0 0
Aperture : 9.0
CFA Pattern : [Red,Green][Green,Blue]
GPS Altitude : 2849.9 m Above Sea Level
GPS Latitude : 35 deg 53' 37.90" N
GPS Longitude : 106 deg 23' 19.39" W
GPS Position : 35 deg 53' 37.90" N, 106 deg 23' 19.39" W
Image Size : 5568x3648
Megapixels : 20.3
Preview Image : (Binary data 750573 bytes, use -b option to extract)
Scale Factor To 35 mm Equivalent: 2.7
Shutter Speed : 1/2500
Circle Of Confusion : 0.011 mm
Field Of View : 65.5 deg
Focal Length : 10.3 mm (35 mm equivalent: 28.0 mm)
Hyperfocal Distance : 1.06 m
Light Value : 15.6

Paulo Lobo · Jan 22, 2019

sar104 said:
You are only looking at a fraction of the data. Here are the full EXIF data from an M2P image file:

File Name : DJI_0184.DNG
File Size : 40 MB
File Modification Date/Time : 2018:12:29 12:49:22-07:00
File Access Date/Time : 2019:01:21 16:14:43-07:00
File Inode Change Date/Time : 2019:01:12 20:20:47-07:00
File Permissions : rwxrwxrwx
File Type : DNG
File Type Extension : dng
MIME Type : image/x-adobe-dng
Exif Byte Order : Little-endian (Intel, II)
Make : Hasselblad
Camera Model Name : L1D-20c
Orientation : Horizontal (normal)
Software : 10.00.08.17
Modify Date : 2018:12:29 12:49:22
Image Width : 5568
Image Height : 3648
Bits Per Sample : 16
Compression : Uncompressed
Photometric Interpretation : Color Filter Array
Strip Offsets : 821680
Samples Per Pixel : 1
Rows Per Strip : 3648
Strip Byte Counts : 40624128
Planar Configuration : Chunky
CFA Repeat Pattern Dim : 2 2
CFA Pattern 2 : 0 1 1 2
CFA Plane Color : Red,Green,Blue
CFA Layout : Rectangular
Black Level Repeat Dim : 2 2
Black Level : 4101 4108 4107 4105
White Level : 65535
Default Scale : 1 1
Default Crop Origin : 4 4
Default Crop Size : 5464 3640
Bayer Green Split : 0
Anti Alias Strength : 1
Best Quality Scale : 1
Active Area : 0 96 3648 5568
Opcode List 3 : (Binary data 12564 bytes, use -b option to extract)
Default User Crop : 0 0 1 1
Subfile Type : Reduced-resolution image
Preview Image Start : 71107
Preview Image Length : 750573
Y Cb Cr Coefficients : 0.299 0.587 0.114
Y Cb Cr Sub Sampling : YCbCr4:2:0 (2 2)
Y Cb Cr Positioning : Co-sited
Reference Black White : 0 255 128 255 128 255
About : DJI Meta Data
Format : image/dng
Latitude : +35.8938600
Longitude : -106.3887196
Absolute Altitude : +2849.93
Relative Altitude : +73.00
Gimbal Roll Degree : +0.00
Gimbal Yaw Degree : -116.00
Gimbal Pitch Degree : -26.00
Flight Roll Degree : -1.60
Flight Yaw Degree : -115.70
Flight Pitch Degree : +0.10
Cam Reverse : 0
Gimbal Reverse : 0
Self Data : DJI Self data
Version : 7.0
Has Settings : False
Has Crop : False
Already Applied : False
Exposure Time : 1/2500
F Number : 9.0
Exposure Program : Program AE
ISO : 400
Exif Version : 0230
Date/Time Original : 2018:12:29 12:49:22
Create Date : 2018:12:29 12:49:22
Exposure Compensation : -0.7
Max Aperture Value : 2.8
Metering Mode : Center-weighted average
Light Source : Daylight
Flash : No Flash
Focal Length : 10.3 mm
File Source : Digital Camera
Scene Type : Directly photographed
Exposure Mode : Auto
White Balance : Auto
Digital Zoom Ratio : 1
Focal Length In 35mm Format : 28 mm
Scene Capture Type : Standard
Gain Control : None
Contrast : Normal
Saturation : Normal
Sharpness : Normal
Serial Number : 0K8TF5W0020136
Lens Info : 28mm f/2.8-11
GPS Version ID : 2.3.0.0
GPS Latitude Ref : North
GPS Longitude Ref : West
GPS Altitude Ref : Above Sea Level
DNG Version : 1.4.0.0
DNG Backward Version : 1.3.0.0
Unique Camera Model : Hasselblad L1D-20c
Color Matrix 1 : 1.2385 -0.7159 -0.0657 -0.0982 1.0352 0.0721 0.0457 0.0241 0.7437
Color Matrix 2 : 0.731 -0.2746 -0.0646 -0.2991 1.0847 0.2469 0.0163 0.0585 0.6324
Analog Balance : 1 1 1
As Shot Neutral : 0.3413333333 1 0.6139088729
Baseline Exposure : 0
Baseline Noise : 1
Baseline Sharpness : 1
Linear Response Limit : 1
Camera Serial Number : 0K8TF5W0020136
Shadow Scale : 1
DNG Private Data : (Binary data 19829 bytes, use -b option to extract)
Calibration Illuminant 1 : Standard Light A
Calibration Illuminant 2 : D65
Profile Name : Embedded
Profile Hue Sat Map Dims : 18 6 1
Profile Hue Sat Map Data 1 : (Binary data 3408 bytes, use -b option to extract)
Profile Hue Sat Map Data 2 : (Binary data 3439 bytes, use -b option to extract)
Profile Embed Policy : Allow Copying
Noise Profile : 0.00025745 2.9e-07
Original Default Final Size : 0 0
Original Best Quality Size : 0 0
Original Default Crop Size : 0 0
Aperture : 9.0
CFA Pattern : [Red,Green][Green,Blue]
GPS Altitude : 2849.9 m Above Sea Level
GPS Latitude : 35 deg 53' 37.90" N
GPS Longitude : 106 deg 23' 19.39" W
GPS Position : 35 deg 53' 37.90" N, 106 deg 23' 19.39" W
Image Size : 5568x3648
Megapixels : 20.3
Preview Image : (Binary data 750573 bytes, use -b option to extract)
Scale Factor To 35 mm Equivalent: 2.7
Shutter Speed : 1/2500
Circle Of Confusion : 0.011 mm
Field Of View : 65.5 deg
Focal Length : 10.3 mm (35 mm equivalent: 28.0 mm)
Hyperfocal Distance : 1.06 m
Light Value : 15.6

So this means that dji mavic 2 pro is ok to use for mapping ? What software are you using? Do you edit the exif getting the altitude from another place ? Do you do this automatic ? I have a telecomunications tower 700 fotos with exif altitude zero from a scan i made, 700 fotos with different altitude, so how do i repair the exif altitude automatic ??

Thanks.

Paulo Lobo · Jan 22, 2019

Hi

I sent so many email´s to dji !

This is the last one :

Dear DJI !

DJI MAVIC 2 PRO is having a problem that everyone is talking about and asking dji to repair !
The EXIF on the fotos are saying that the gps altitude is ZERO when the drone is 10...20...30.. meters altitude !
Its always zero on the EXIF fotos gps altitude !

This is not ok for using dji mavic 2 pro to make mapping and 3dstatue...

We need this repair as soon as possible !
This is a problem only on dji mavic 2, i have dji mavic 2 pro and he has this problem !

DJI MAVIC PRO is ok
DJI PHantom 4 is OK
DJI Phanom 4 pro is ok
Inspire 1 is ok

So Repair this problem on dji mavic 2 pro !!

There is no altitude on the EXIF information fotos.

I use dji 4 go last version with last firmware on my dji mavic 2 pro and i have no ZERO on the gps EXIF information FOTOS !

Please repair !! As Soon as Possible.

I send so many emails to dji about this and i got no solution !
Other persons have this problem and asked to dji a solution !
DJI is not giving the solution !! WHY ??

The Altitude is on dji 4 go screen when drone lift up, so why is not in the fotos EXIF ???

Repair this as soon as possible !!

Do your wonderfull job and repair this situation ! We need it repair !

Keep the good image of your company DJI ! A company that solves the problems when the costumers says that there is a problem !

Do not keep making questions when you know there is a problem in the EXIF fotos of dji mavic 2 pro !

We need the gps altitude in the EXIF !!

Paulo Lobo

De: Support <[email protected]>
Enviado: terça-feira, 22 de janeiro de 2019 04:15
Para: PAULO LOBO
Assunto: [DJI] 回复： No altitude on the dji mavic 2 pro fotos.

##- 请在此行以上输入您的回复 -##
您的请求（20530）已更新。要添加另外的评论，请回复此电邮。

Lisa Fedane （DJI）
1月22日 CST12:15
Hi Paulo,

It looks like there is a misunderstanding here - you have reached out to [email protected] which is a support line that answers questions for software developers using our SDK. It appears that you are only using DJI GO and your drone - these questions should be directed to [email protected]. I apologize that this was not caught earlier.

Warm Regards,
Lisa Fedane
DJI Developer Support

PAULO LOBO
1月22日 CST06:54
Look here :
Im not the only one with this problem in the dji mavic 2 pro altitude not show on EXIF fotos....
MAVIC 2 pro EXIF ISSUE (gps,coordinates)
MAVIC 2 pro EXIF ISSUE (gps,coordinates) | DJI FORUM<MAVIC 2 pro EXIF ISSUE (gps,coordinates)>
Hi, sorry for the inconvenience. Regarding your concern, the camera is taking the fusion height of the flight control to generate the EXIF information of the photo, which is calculated by a specific algorithm by referring to two measurement heights as Barometer and GPS.
forum.dji.com
DJI must repair this !
We pay for a dji mavic 2 pro able to do mapping ! So we need the GPS altitude in the EXIF fotos !
Paulo Lobo
________________________________
De: PAULO LOBO <[email protected]>
Enviado: segunda-feira, 21 de janeiro de 2019 22:43
Para: Support
Assunto: RE: [DJI] 回复： No altitude on the dji mavic 2 pro fotos.
Dear Lisa Fedane - DJI
What is DJI´s Sample App ???
Im working with the last version of DJI Go 4 !
I already answer this question before, why dji is always asking ???
Paulo Lobo
________________________________
De: Support <[email protected]>
Enviado: sexta-feira, 18 de janeiro de 2019 22:36
Para: PAULO LOBO
Assunto: [DJI] 回复： No altitude on the dji mavic 2 pro fotos.

PAULO LOBO
1月22日 CST06:43
Dear Lisa Fedane - DJI
What is DJI´s Sample App ???
Im working with the last version of DJI Go 4 !
I already answer this question before, why dji is always asking ???
Paulo Lobo
________________________________
De: Support <[email protected]>
Enviado: sexta-feira, 18 de janeiro de 2019 22:36
Para: PAULO LOBO
Assunto: [DJI] 回复： No altitude on the dji mavic 2 pro fotos.

PAULO LOBO
1月20日 CST02:50
Hi Lisa,
This test was with dji go 4 last version !
I really need this problem repair.
I search the internet and i found that this is a problem with a lot of persons that have dji mavic 2 pro, some people say that they have EXIF data with zero altitude like i also have, other people say that the value is not correct !!
So we need DJI to repair this problem as soon as possible.
We pay for a dji mavic 2 pro to make mapping ortho fotos, but with no altitude on the EXIF its not possible to do this mapping...
Look :
mavic pro 2 exif GPS Altitude not working...
mavic pro 2 exif GPS Altitude not working... | DJI FORUM<mavic pro 2 exif GPS Altitude not working...>
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.
forum.dji.com
MAVIC 2 pro EXIF ISSUE (gps,coordinates)
MAVIC 2 pro EXIF ISSUE (gps,coordinates) | DJI FORUM<MAVIC 2 pro EXIF ISSUE (gps,coordinates)>
Hi, sorry for the inconvenience. Regarding your concern, the camera is taking the fusion height of the flight control to generate the EXIF information of the photo, which is calculated by a specific algorithm by referring to two measurement heights as Barometer and GPS.
forum.dji.com
Incorrect EXIF GPS and Elevation
Incorrect EXIF GPS and Elevation | DJI Mavic Drone Forum<Incorrect EXIF GPS and Elevation>
Mavic 2 Pro flight and pictures excellent, but image EXIF data shows altitude was a bit over 115 million meters...which would be impressive if true.
mavicpilots.com
Paulo Lobo
________________________________
De: Support <[email protected]>
Enviado: sexta-feira, 18 de janeiro de 2019 22:36
Para: PAULO LOBO
Assunto: [DJI] 回复： No altitude on the dji mavic 2 pro fotos.

Lisa Fedane （DJI）
1月19日 CST06:36
Hi Paulo,

Did you run this test with DJI's Sample App, your own application or with DJI Go?

Thanks,
Lisa Fedane
DJI Developer Support

PAULO LOBO
1月13日 CST23:53
PAULO LOBO compartilhou um arquivo do OneDrive com você. Para exibi-lo, clique no link abaixo.
<default>
[https://r1.res.office365.com/owa/prem/images/dc-jpg_20.png]<https://1drv.ms/u/s!Anh43bnCcxb_g07Xsepjb7EriMsz>
DJI_0882.JPG<default>
Hi
Dear Lisa
Today i made some more test and there is no altitude on the EXIF data fotos.
Attached to this email you find two fotos from today test, one is shared by onedrive, other is attached this email...
All fotos have zero altitude Exif.
Its very urgent to have this repair! I have costumers waiting for 3d mapping and with no altitude on the fotos its impossible to build photogrametry 3d....
Please repair
Paulo Lobo
________________________________
De: Support <[email protected]>
Enviado: quinta-feira, 10 de janeiro de 2019 23:24
Para: PAULO LOBO
Assunto: [DJI] 回复： No altitude on the dji mavic 2 pro fotos.
附件
DJI_0881.JPG

PAULO LOBO
1月12日 CST06:02
Hi,
Dear Lisa
I have 815 fotos around a tower, the drone was taking fotos to build a 3d ortho.
I was using dji go 4 last version and last firmware on my dji mavic 2 pro.
All the 815 fotos have no altitude ( altitude zero ) and i was at almost 90metters high from sea.
I also made a test at home and no altitude was in the fotos.
But tomorrow i run a test again, and ill check !
Thanks
Paulo Lobo
________________________________
De: Support <[email protected]>
Enviado: quinta-feira, 10 de janeiro de 2019 23:24
Para: PAULO LOBO
Assunto: [DJI] 回复： No altitude on the dji mavic 2 pro fotos.

Lisa Fedane （DJI）
1月11日 CST07:24
Hi Paulo,

Thank you for contacting DJI Developer Support. The EXIF data should show the altitude, so I want you to run a test - please take a photo using our Sample App with the same drone, in the same location and let me know if the altitude is still missing. If it is not, send me a code sample and we can review it for you.

Warm Regards,
Lisa Fedane
DJI Developer Support

PAULO LOBO
1月4日 CST06:08
PAULO LOBO compartilhou um arquivo do OneDrive com você. Para exibi-lo, clique no link abaixo.
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Hi.
Dear Dji Support and DJI Dev Support
Why the dji mavic 2 pro fotos have zero altitude, in the parameters of the foto ??
See attached the foto please.
We have gps coordinates, but zero on the altitude !!
Paulo Lobo
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sar104 · Jan 22, 2019

The EXIF data that I posted are directly from the images (both RAW and JPEG) - that's just an EXIF data dump using Exiftool. It contains two kinds of altitude data - barometric (relative to takeoff point) and GPS (relative to MSL). The barometric is fairly accurate, to within a couple of meters. The GPS altitude is not very accurate, with errors of tens of meters. I'm not sure why that is, given that the theoretical vertical error is only around 1.5 x the horizontal error.

Anyway - if you want to use altitude for surveying you will need to use the barometric values added to the absolute altitude of the takeoff point. But there is no point in harassing DJI when the data are there but you simply don't know how to access it.

sar104 · Jan 22, 2019

That discrepancy in GPS altitude data has been bothering me for some time, so I took a closer look. There is a very simple explanation. The aircraft records several different altitude-related parameters in the log file: GPS altitude AMSL, barometric altitude AMSL and barometric altitude relative to the takeoff elevation. Looking at those data for a flight, and including GPS altitude relative to the takeoff location (by subtracting the known ground elevation) shows the following:

Immediately obvious here is that the GPS altitude at launch is correct to within a couple of meters, while the barometric altitude is high by 55 meters. During the flight the relative barometric altitude and relative GPS altitude also agree to within 5 meters or so, with a systematic altitude-dependent offset in the same direction as the offset in absolute barometric altitude.

What is happening here is that the absolute barometric altitude, and the change in relative barometric altitude, are based on the standard atmospheric model, which is temperature dependent. At the time of this flight the atmosphere is colder and denser than the standard model, and so the change in pressure with altitude is greater than for a standard atmosphere. That is why the absolute barometric altitude is too high, and the relative barometric altitude is also high. The GPS altitude, in contrast, is accurate to within a few meters, as expected from theory.

Now, with regard to the GPS altitude data in the EXIF - it's not GPS altitude at all - it's mislabeled. I took a number of photos at the maximum altitude on this flight, and the EXIF GPS altitude recorded was actually the absolute barometric altitude (3075 m) and not the (correct) GPS altitude (3010 m).

I've checked a number of flights to confirm that this is consistently the case.

@Meta4 - this explains why we see what we thought to be evidence of large errors in the GPS altitude in the EXIF data. If you look at the log files for some of your flights you should find that the actual, recorded GPS altitude values are very close to correct and that the recorded EXIF GPS altitude is in fact the absolute barometric altitude instead.

Paulo Lobo · Jan 26, 2019

Look, this is too much talking, when we have only one problem !

DJI MUST REPAIR THE GPS ALTITUDE ON EXIF FOTOS FOR DJI MAVIC 2 PRO !

A foto taken at 10meters altitude is not a foto taken at zero altitude.

Two days ago dji sent another firmware ...300 but the problem is not solved..

This is so so so bad for dji image...

sar104 · Jan 26, 2019

Paulo Lobo said:
Look, this is too much talking, when we have only one problem !

DJI MUST REPAIR THE GPS ALTITUDE ON EXIF FOTOS FOR DJI MAVIC 2 PRO !

A foto taken at 10meters altitude is not a foto taken at zero altitude.

Two days ago dji sent another firmware ...300 but the problem is not solved..

This is so so so bad for dji image...

And you obviously are not reading - there is no GPS altitude recorded - it is the barometric altitude, both relative and absolute. In post #8 you were claiming that there were no altitudes at all in the EXIF data, so you are not in a good position to complain. I'm pretty sure that DJI's image is not suffering from this at all, since there are very few who care.

Paulo Lobo · Jan 26, 2019

sar104 said:
And you obviously are not reading - there is no GPS altitude recorded - it is the barometric altitude, both relative and absolute. In post #8 you were claiming that there were no altitudes at all in the EXIF data, so you are not in a good position to complain. I'm pretty sure that DJI's image is not suffering from this at all, since there are very few who care.

DJI Phantom 4, dji phantom 4 pro, dji mavic pro, inspire 1, inspire 2, all of them have the value gps altitude in EXIF.

Also the softwares to work the fotos ask for the gps altitude in the EXIF fotos, so its necessary.

If you dont understand that, its no problem.

Dji as assume that there is a problem in the firmware, the first dji mavic 2 pro firmware was with this information in the EXIF fotos, the second firmware, and the last ones, there is no GPS Altitude in EXIF.

So we must wait for the repair.

Bye.

JDawg · Jan 26, 2019

Paulo Lobo said:
Look, this is too much talking, when we have only one problem !

DJI MUST REPAIR THE GPS ALTITUDE ON EXIF FOTOS FOR DJI MAVIC 2 PRO !

A foto taken at 10meters altitude is not a foto taken at zero altitude.

Two days ago dji sent another firmware ...300 but the problem is not solved..

This is so so so bad for dji image...