Interpolation for Geoid GeoTif?

[c-r-o-n-o-s]

Hello.

Does anyone know exactly how the Geotiffs are interpolated for the Vertical Elevation Correction?

I have a geotiff for geoid undulation with a resolution of "only" 310*284 pixels.
(It extends over several hundred kilometers).

In my survey program it says that there bilinear is interpolated in between.

How does Metashape interpolate here?

[c-r-o-n-o-s]

I think it's bilinear.
The results are now the same as in my survey program.