Anyone know of a stand alone program that will compute state combine grid factor using Geoid 12A ? for a given point or site average .
I would say CORPSCON but I'm not sure that it uses Geoid12A yet. I don't think this is a real problem though. The geoid model is used in the computation of the sea-level correction and I don't think a couple of cm difference in the model is going to add any significant error. We are talking about changes in the 9th decimal place which translates to a change of about .1 millimeter, definitely not a problem if you are using a combined factor.
> I would say CORPSCON but I'm not sure that it uses Geoid12A yet.
These instructions for loading Geoid09 can be easily adapted to load Geoid12a.
Current download says combine scale is wrong dont use.