Camera Substract -45m in Altitude

[Payne]

Hey,

I need to substract a value of -45m from camera altitude in Agisoft.

By tried to use the "convert reference" function  WGS 84 to ETRS89 (see screenshot) and substract the value, but the end values does not fit (see below).
Normally for example 186.65-45 = 141.65

See Example 1/ Result 1 by -45
-> From 186.65 to 222.70 =  ADD 36,05. WHY?!

See Example 2/Result 2 by +45
-> From 186.65 to 150.60 =  Subtract 36,05. WHY?!

How to substract a value of -45m in altitude of all cameras?

Best wishes and thanks,
Norman

[Paulo]

Hello Payne,

the problem is that the Z axis you are using in datum transformation does not represent height or altitude but rather geocentric Z axis (from center of earth to North Pole).

To substrct 45 m from all camera height coordinates try using following from github Agisoft https://github.com/agisoft-llc/metashape-scripts/blob/master/src/add_altitude_to_reference.py.

Should do the trick.