AnsweredAssumed Answered

Conversion of Trimble GPS Data to NAD83(1986) in ArcGIS

Question asked by KHeulitt on Dec 12, 2019
Latest reply on Jan 14, 2020 by JJCusick@nps.gov_nps

I realize there are other posts on this topic but I'm not understanding the logic of the consensus so I'm hoping that someone can enlighten me.


I'm using a Trimble Geo7X GPS unit and post-processing the data using the base station positions from Trimble's base station list.  Therefore, I am confident that my data is in a newer realization of WGS84 which is essentially equivalent to ITRF00.  Following post-processing I export my data from Pathfinder Office to ArcGIS keeping it in the WGS84 datum.  All of my GIS map documents and data are in NAD83(1986).


I understand that:

NAD83(1986) = original WGS84

NAD(1986) <> current WGS84/ITRF00


In ArcGIS, I either let the program reproject my GPS data "on the fly" or reproject to NAD83(1986).  The consensus seems to be that no datum transformation/shift should be applied in this conversion.  If this is correct, can anyone explain why?  If NAD(1986)<>current WGS84/ITRF00  how is a datum shift not needed?