P4P - Inconsistent Altitude in Pre-Programmed Missions

[Kristina Fowler]

I use a popular flight plan app that lets you program missions with long/lat/alt. This particular mission is a simple one point mission at a designated latitude, longitude and altitude. The mission is saved and I use it on a recurring basis - always careful not to bump the settings. This month, it shows a fairly severe disparity in altitude vs the previous month, despite no changes to the programmed mission.

AC: Phantom 4 Pro
Device 1: iPad Pro (WiFi only)
Device 2: iPhone 8S (with Hot Spot)

Of note: While I usually connect the iPad to the iPhone via Hot Spot, I cannot say with 100% certainty that it was connected for this mission. The app does not require a cellular connection.

Hoping I could get some suggestions as to why the disparity in altitude between the two missions when technically it's the exact same spot in the sky (X, Y, and Z). FYI - I verified that the long/lat values are identical. Thanks in advance...

 

[Meta4]

This month, it shows a fairly severe disparity in altitude vs the previous month, despite no changes to the programmed mission.

Hoping I could get some suggestions as to why the disparity in altitude between the two missions when technically it's the exact same spot in the sky (X, Y, and Z). FYI - I verified that the long/lat values are identical.

You're looking at Exif data for those altitude figures?
Ignore it .. it's of very variable (in)accuracy.
You can confirm that by taking a test shot on the ground at a known altitude.
Did you see the height displayed on your screen while flying? It would have been much more accurate.

Here's an example of how dodgy Exif altitudes can be: