altitude vs altitude

[John1945]

can anyone explain to me what the altitude number recorded in image files exif data really means. e.g. I am flying at 136 feet AGL according to the app but get a value of 337 feet from the image exif data.

 

[AMann]

can anyone explain to me what the altitude number recorded in image files exif data really means. e.g. I am flying at 136 feet AGL according to the app but get a value of 337 feet from the image exif data.

What was your elevation AMSL? Just wondering if its recording from GPS, which isn't that accurate for measuring verticals anyways due of the type of GPS they have.

 

[Meta4]

can anyone explain to me what the altitude number recorded in image files exif data really means. e.g. I am flying at 136 feet AGL according to the app but get a value of 337 feet from the image exif data.

The Exif altitude data is a rough approximation of the drone's height above sea level.
It's not the same as the height above launch point which is shown on your screen.

 

[paulatkin73]

The Exif altitude data is a rough approximation of the drone's height above sea level.
It's not the same as the height above launch point which is shown on your screen.

isn`t it the barometer`s data? so it may differ from day to day, depending upon the current pressure?

 

[Meta4]

isn`t it the barometer`s data? so it may differ from day to day, depending upon the current pressure?

It comes from the barometer ... just like the altitude displayed on the screen in the app.
But the screen altitude is an accurate altitude relative to the launch point while the Exif altitude is a rough approximation of altitude above sea level derived from the barometer data.

 

[AMann]

It comes from the barometer ... just like the altitude displayed on the screen in the app.
But the screen altitude is an accurate altitude relative to the launch point while the Exif altitude is a rough approximation of altitude above sea level derived from the barometer data.

I did not know that, so it’s really just based on the average millibar pressure at sea level. Probably still a lot more accurate than what the GPS could provide.

It would be great if one could get a topo overlay showing ground elevation AMSL while flying.

 

[Meta4]

so it’s really just based on the average millibar pressure at sea level. Probably still a lot more accurate than what the GPS could provide.

Not necessarily very accurate as this example demonstrates:
Although the Exif shows it as GPS altitude, it's really derived from barometer data

 

[AMann]

Sub shot?

Too bad there’s not a way to calibrate it.

 

[Meta4]

Sub shot?

There's a sub on the research vessel.
It was just coming back from this expedition to the deepest part of the ocean.

The Japan Times

News on Japan, Business News, Opinion, Sports, Entertainment and More article expired

www.japantimes.co.jp

 

[AMann]

There's a sub on the research vessel.
It was just coming back from this expedition to the deepest part of the ocean.

The Japan Times

News on Japan, Business News, Opinion, Sports, Entertainment and More article expired

www.japantimes.co.jp

Almost 8,180 meters- that’s over 810 atmospheres or almost 12,000 psi. Amazing! I saw some plexiglass windows that were swapped out of a submersible that went probably only half as deep, and the plastic was warped inwards due to the pressure, they were at least 6-inches thick!