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JPG vs DNG Altitude Meta data differences
1389 16 2016-2-22
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Caddwizard
lvl.3
Flight distance : 453788780 ft
Australia
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How does this happen?


Here is something I posted on other forums. No one could answer.

JPG vs DNG Altitude information

Both my Inspires I1x3 & I1Px5 when shooting J+R show different altitudes for the same shot. Video SRT shows teh same heights as DNG



EXIF properties shown are an example with these details (grey Lightroom CC, white Windows properties)



1. Taken sitting on the ground in this example. Note the differences in altitude are consistently spaced when off the ground.

2. Location is near a beach. Google Earth says my takeoff location was at an altitude of 8m.

3. Video SRT files show heights consistent with the DNG values

Not sure why two altitude values. Ultimately the DNG altitudes are what I need to rely upon.



FYI

Have greyed out the EXIF location information of the screen captures (its all there just covered over)




2016-02-18 06.52.29.jpg
2016-2-22
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Harb
lvl.4

Australia
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Thats really odd......its like one is recording or referencing the incorrect datum point or alt data
2016-2-22
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DJI-Tim
DJI team

Hong Kong
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ohh very interesting... i'll try to get our engineers to take a look at it
2016-2-22
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DJI-Tim
DJI team

Hong Kong
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I got some information for you: JPG shows the height above the sea level. DNG shows the altitude from the take off point.
2016-2-23
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YOO SANG OH
lvl.3
Flight distance : 193294 ft
South Korea
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i have same problem since january  2016

dng

dng

jpg

jpg
2016-2-23
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DJI-Tim
DJI team

Hong Kong
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YOO SANG OH Posted at 2016-2-23 21:16
i have same problem since january  2016

Hey Yoo! As I already said:  JPG shows the height above the sea level. DNG shows the altitude from the take off point.
Hope it explains the difference
2016-2-23
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Caddwizard
lvl.3
Flight distance : 453788780 ft
Australia
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DJI-Tim Posted at 2016-2-23 19:20
I got some information for you: JPG shows the height above the sea level. DNG shows the altitude fro ...

Had a feeling it was something like that. I had a shoot one day not far from the beach, the next day I was in the mountains.

2 questions if I may.

1. Any way to set JPG to height above ground, problem is I need to take shots for developers at heights (lots of them) covering a full 360 view. JPGs are fine, DNG take too long to save and require post edit for the client to view.

2. Is that GPS or barometric height above sea level. I use an iPad Air 2 Cellular.

Many thanks your information
2016-2-24
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YOO SANG OH
lvl.3
Flight distance : 193294 ft
South Korea
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thanks for your answer.
but before january, even though format was jpg, state was normal.
there are some problem after latest firmware
2016-2-24
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DJI-Tim Posted at 2016-2-24 15:49
Hey Yoo! As I already said:  JPG shows the height above the sea level. DNG shows the altitude from ...

Is this going to be fixed?  I noticed the GPSAltitude in the Exif data hasn't been put back to relative altitude in the latest firware update either.   

I need the relative height back to give to clients.  How come it was changed without notification??

And why would anyone need height above an ISA defined sea level?  We're not flying QNH with commercial airlines..  :/
2016-3-16
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Farnk666
Captain
Flight distance : 1711394 ft
Australia
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DJI-Tim Posted at 2016-2-24 15:49
Hey Yoo! As I already said:  JPG shows the height above the sea level. DNG shows the altitude from ...

The Inspire has no way of determining height above sea level.
2016-3-16
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Harb
lvl.4

Australia
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would the onboard GPS give that info ?
2016-3-16
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DJI-Tim
DJI team

Hong Kong
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Farnk666 Posted at 2016-3-17 11:20
The Inspire has no way of determining height above sea level.

Yes inspire can measure the altitude above the sea level.
2016-3-16
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DJI-Tim
DJI team

Hong Kong
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phil@hotmail.co Posted at 2016-3-17 11:12
Is this going to be fixed?  I noticed the GPSAltitude in the Exif data hasn't been put back to rel ...

it has been reported already. the issue will be fixed
2016-3-16
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DJI-Tim
DJI team

Hong Kong
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Harb Posted at 2016-3-17 11:43
would the onboard GPS give that info ?

yeah, you got it, Harb!
2016-3-16
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njabinc
lvl.3

United States
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DJI-Tim Posted at 2016-3-17 03:07
yeah, you got it, Harb!

This is all very comical as I debated this information on here months ago just in different context. What this means is that the Inspire carries everything necessary to provide real time accurate altitude information instead of the simple and incomplete altitude from take off. The height above sea level at any GPS location is embedded information in multiple sources. Given the Inspire already accesses and uses this data, in its preflight warmup it could simply set its relative altitude compared to sea level just like a pilot in any other aircraft. Then during flight it would need to compare the recorded preflight data above sea level compared to current level compared to sea level at it's GPS coordinates and then further integrated with the on board sensors data indicating change in altitude from take off to provide a check and increased accuracy. This would naturally lead to having real time accurate above ground altitude data provided. This is truly necessary and sought by many. For instance I happen to live in a valley and I must reset the altitude restriction and ignore warnings in preflight along with during flight so I don't burn it into a side of two different mountains that require me to increase my altitude by almost 300 feet to retain a safe distance from the 125 foot trees. Maintaining a safe altitude while ascending above the suggested altitude limitation though necessary isn't a comfortable action as it requires seat of the pants judgement to do so. For the record I went as far as to examine flight maps to ascertain the height of the topography surrounding my location. Given the complexity of the equipment and the information it's already decimating, I've always found it silly that one of the largest concerns of the regulatory agencies, the non drone public, and a large segment of operators is adherence to as of now suggested altitudes limitations when the technology and data is all readily available to allow accurate real time data to the operator. I was told it was impossible by everyone with a DJI prior to their screen name among others and I strongly disagreed at the time. Now through the information provided in this thread it's clear I was indeed correct. While in the past I have questioned the motives of the multiple DJI reps here and haven't agreed with certain actions taken by DJI and then supported by them I recognize the tenor of posts and actions taken indicate they not only care about their jobs and the company providing them but also and more importantly about the community purchasing and using them. I have seen increasing genuine efforts to help however possible and communication of honest information whether good or bad. It's refreshing and appreciated. I would ask that my request be forwarded to engineering as I feel given the level of hardware and software technology presently integrated this would require very little additional code to achieve and it would eventually be found in a firmware update .
2016-3-17
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Farnk666
Captain
Flight distance : 1711394 ft
Australia
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DJI-Tim Posted at 2016-3-17 15:05
Yes inspire can measure the altitude above the sea level.

If based upon GPS data, then that is not particularly accurate.
2016-3-17
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fansc88ec810
lvl.2
Flight distance : 203812 ft
United States
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DJI-Tim Posted at 2016-2-23 00:20
I got some information for you: JPG shows the height above the sea level. DNG shows the altitude from the take off point.

I know this is an old thread. But with my mavic I am seeing this problem. But your explanation does not explain my altitude data...
I took 5 photos at the heights of 10ft,20ft,50ft,100ft and 250ft.
Here are the altitude data from jpg and dng
DNG [the right side number is in metres]:
10ft: 3.3m
20ft: 6.3m
50ft: 15.5m
100ft: 30.8m
250ft: 76.4m

JPG:
10ft: 50.469m
20ft: 47.469m
50ft: 38.269m
100ft: 22.969m
250ft: 22.63m

As you can see, the DNG altitude matches.
But the jpg altitudes are way off. Not only that, as the aircraft went higher, the jpg altitude decreases!

Any explanation for this?

Thanks
2017-3-26
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