Sar, As mentioned, I am not certain what the pressure was, but I live at sea level, and the pressure generally hovers around 1015... 1020 is really quite high, and 1024 or so is very high.
I took a couple of images yesterday, in the same spot, at the same time, 1 with the Mavic Air, the other with the
Mavic 2 Pro.... Have a look at the Exif.. the results speak for themselves.... VERY different Altitudes, NO XMP data in the
M2P, etc....
Actually, the Mavic Air results are what I would have expected for this particular location......
If DJI can get it right for the Air, why cant they get it right for the
M2P, (or at least get it consistent... Minus 16.2 mtrs for the
M2P, and Plus 1.2 for the Air (which I reckon is about right)
I DO realise the figures are barometric etc, and that they will change according to weather pressure/temp variations..... but nevertheless..... there IS a problem here.... and its DJIs.
cheers all.... I am NOT complaining, I just want to get to a point where I can trust the data.... I'm not there yet...... haven't been since the issue of the
M2P last August!
Please ignore the quality of the images here... I wasn't trying to get a nice image.. just the starting altitude.... and I didn't actually take off... I do know that the relative altitudes would have been OK... but the starting altitude is the one I want to be correct also.
I don't think those files show any of the things that you think they do. First of all, they both have exactly the same XMP fields:
Mavic Air:
---- XMP-x ----
XMP Toolkit : Image::ExifTool 11.31
---- XMP-rdf ----
About : DJI Meta Data
---- XMP-dc ----
Format : image/jpg
---- XMP-drone-dji ----
Absolute Altitude : +1.20
Cam Reverse : 0
Flight Pitch Degree : -0.20
Flight Roll Degree : -7.10
Flight Yaw Degree : +0.50
Gimbal Pitch Degree : +0.00
Gimbal Reverse : 0
Gimbal Roll Degree : +0.00
Gimbal Yaw Degree : +0.00
Latitude : -26.4004708575672
Longitude : 153.068872690185
Relative Altitude : +0.00
Self Data : DJI Self data
---- XMP-tiff ----
Make : DJI
Camera Model Name : Test_Pro
---- XMP-xmp ----
Create Date : 2017:09:14
Modify Date : 2017:09:14
---- XMP-crs ----
Already Applied : False
Has Crop : False
Has Settings : False
Version : 7.0
---- XMP-x ----
XMP Toolkit : Image::ExifTool 11.31
---- XMP-rdf ----
About : DJI Meta Data
---- XMP-dc ----
Format : image/jpg
---- XMP-drone-dji ----
Absolute Altitude : -16.23
Cam Reverse : 0
Flight Pitch Degree : -5.60
Flight Roll Degree : -4.70
Flight Yaw Degree : -3.80
Gimbal Pitch Degree : +0.00
Gimbal Reverse : 0
Gimbal Roll Degree : +0.00
Gimbal Yaw Degree : +8.10
Gps Latitude : 26.400471
Gps Longitude : 153.068873
Relative Altitude : +0.00
Self Data : Self data
---- XMP-tiff ----
Make : DJI
Camera Model Name : Test_Pro
---- XMP-xmp ----
Create Date : 1970:01:01
Modify Date : 1970:01:01
---- XMP-crs ----
Already Applied : False
Has Crop : False
Has Settings : False
Version : 7.0
Secondly, looking at the altitude data fields:
Mavic Air
GPS Altitude Ref : Above Sea Level
Absolute Altitude : +1.20
Relative Altitude : +0.00
GPS Altitude : 0 m Above Sea Level
GPS Altitude Ref : Below Sea Level
Absolute Altitude : -16.23
Relative Altitude : +0.00
GPS Altitude : 16.2 m Below Sea Level
The Mavic Air fields are clearly incorrect. In fact that looks like an earlier problem with the firmware on some aircraft where the absolute altitude (barometric) always showed up as 1.20 m. Have you checked to see if that field ever reports real altitudes? And the GPS altitude field is just showing as zero, which is almost certainly spurious.
The
Mavic 2 data shows that DJI has changed it slightly in the latest firmware - previously when the absolute barometric altitude was negative the GPS altitude field was set to zero, but now it is reporting the negative altitude. It's still not the GPS altitude though.
