Setting vertical coordinate system seems to be not recognized

[ThomasBeckerDK]

I am trying to assign a vertical coordinate system to a mosaic dataset, and while the 'Define Projection' tool runs nicely through when I point it to the mosaic dataset (dem), it fails when I point it directly to the image (dem\Image) within the mosaic dataset.

In the subsequent 'Geodesic Viewshed' tool it doesn't matter if I select the entire mosaic dataset (dem), or the image part of it (dem\Image) the warning is all the time there, and it seems the defined vertical coordinate system is not applied/recognized.

How can I get rid of this warning, indicating that I do not have set the vertical coordinate system, and run a proper geodesic viewshed analysis?

[CathrineMoore]

It's unfortunate to see that this post has not had any responses.  It is a known problem!  Here is a response from a separate group discussion that may provide some insight:  "...try using NAD83(CSRS)v8 as your vertical. It references the GRS80 ellipsoid which would be the same as your horizontal coordinate system. CGVD1928 does not reference a spheroid, it is a tidal based vertical datum so I would guess that's what is causing your warning message.

CGVD1928 and CGVD2013 both provide orthometric heights and the geodesic viewshed tool needs ellipsoidal heights. You would have to transform CGVD1928 or CGVD2013 to ellipsoidal heights and I don’t think ArcGIS Pro has those transformations without additional installation files (https://pro.arcgis.com/en/pro-app/latest/help/mapping/properties/arcgis-coordinate-systems-data.htm).

Install supplementary coordinate system files—ArcGIS Pro | Documentation"