How do I convert altitude to Mean Sea Level altitude?

Question

For whatever dumb reason, Android location altitude is WS84 altitude and not the one which most users expect, which is mean sea level altitude.

Can I make the conversion with ArcGIS Runtime? From WGS84 to EGM2008 or something.

I thought I was real smart and could figure it out.

Geometry vprojected = GeometryEngine.project(currentLocation, SpatialReference.create(4326, 3855));

This looks like what a reasonable person would do to project to Mean Sea Level. The vertical spatialreference is EGM2008.

It doesn't crash or give any error messages.

The problem:

It doesn't change the z value of the point. Not the slightest bit.

What do I need to do?

MikeWilburn · Answer

Hi Nathan,

Vertical datum transformations are not currently supported in the Runtime. Calling the `project` method will only transform the horizontal coordinates between two different datums or spatial references.

There are, however, a number of vertical coordinate transformations available in our desktop software ArcGIS Pro that can handle this for you. Here's a link you may find helpful: Vertical coordinate systems—Properties of maps | ArcGIS Desktop

To vertically transform between WGS 1984 and EGM 2008, I believe you'd require geographic transformation WKID `110018` or `110019`.

Cheers,

Mike

NathanDMellor · Answer

And in case it comes up:

DatumTransformation transform = TransformationCatalog.getTransformation(SpatialReference.create(4326), SpatialReference.create(4326,3855));

returns null.