Vertical coord system for British National Grid?

[OrleansOscar]

I created a DSM from Lidar data supplied by DEFRA. It's 2014 1m - I then ran it through mosaic to new raster to join the tiles. When I try to use this in a Geodesic Viewshed I get the following warning:

Input elevation raster should have a vertical coordinate system that has heights referenced to a spheroid.

So, I am projecting the raster again, it's British National Grid - what is the suggested vertical coord system for this? Can anyone recommend any reading on this to aid selecting the right system?

Many thanks.

[Robert_LeClair]

@MelitaKennedy - would you know the answer to this question?

[MelitaKennedy · Accepted solution]

@Robert_LeClair Thanks for pointing this out!

The UK uses ODN AKA Newlyn, EPSG:5701. 

We currently have transformation between Newlyn and EVRF2000 or EVRS2000. These are actually the same transformation just using different names for the target coordinate reference system. We're working on implementing OSGM15 and OSGM02 but the grid file format is not one we already support so it needs extra work. We don't yet for which version it'll be ready.

Melita

[OrleansOscar]

Brilliant, thank you!