H & V DATUM TABLE

[ChuckTurlington]

Hello,

I am using ArcMap 10.4.1.

I have a need to know the likely vertical datum used with the UTM83, zone 16, projected horizontal datum, and have to ask if there is a table of horizontal datums matched to their corresponding vertical datum for a particular date?  I know NGS has many sites dedicated to just a particular geoid or ellipsoid but nothing that summarizes the intended combination of horizontal and vertical datums for a given date, at least not that I have found.

[JimCousins · Accepted solution]

There is no direct correlation between a horizontal datum and vertical datum. They can be mixed, so you will need to check the metadata if it is available. Even data collected prior to the inception of NAVD88 may have been converted to NAVD88 for analysis with other NAVD88 data, and the same holds true for NGVD29. Your option is to try and get the vertical reference from the source.

Regards,

Jim

[MelitaKennedy]

Geoid models (converting between ellipsoidal heights and orthometric heights) are usually tied to a particular GCS, like geoid12b should be used with NAD83 (2011), but as Jim says, the gravity-related vertical coordinate systems/datums like NAVD88 and NGVD29 aren't strongly tied to a particular GCS.

[ChuckTurlington]

Is NAD83 (2011) the only horizontal datum tied specifically to geoid 12b, or are there others that have strong ties to geoid12b or other vertical datums?  I am trying to narrow down the guess work to know what a likely vertical datum could be for a particular coordinate system, such as UTM83.

[MelitaKennedy]

It's all based on the GCS. Any of the NAD83 realizations are more likely to be using NAVD88, but it's not 100%. Depending on where the data is, the differences between the NAD83 realizations (starting with HARN) won't make much difference when using geoid12b. That is, ellipsoidal heights will differ depending on which realization is being used, but when using that location to interpolate the offset between ellipsoidal and geoid surfaces, should not make that much difference.

[JoelCusick]

I fear to tread on this topic, but its my understanding from sitting in so many NGS presentations on this topic, the phrase above :"geoid12b should be used with NAD83 (2011)" should be better written as "geoid12b must be used with NAD83 (2011)".  The Datum Tag and Epoch of NAD83 2011 (Epoch 2010.0) is tied too the Orthometric H using Geoid12A/12B.  I'm not a surveyor, but I heard these two MUST be associated with each other.  That is, of course if the data stored in this table was derived from say an OPUS solution, or post Processed with or RTN streamed from a service bound to NAD83 (2011).  Again, not a surveyor,  nor am I a geodesist. I'm merely a biologist by training who tries to tie all my federal data to NSRF.

Joel