The implementation of GDA2020 is drawing near! In an effort to be ready before time I have downloaded the NTv2 Grid Shift Binary (GSB) transformation grid from ISCM (available here) who are the official custodians of all things GDA2020 related. I am using the
GDA94_GDA2020_conformal_and_distortion.gsb as well as AUSGeoid2020 (available here).
ArcGIS 10.5 does have GDA2020/MGA2020 in the list of available coordinate systems.. a good start. ArcGIS 10.2 does not recognize GDA2020 calling the CRS "custom" but locating correctly.
When transforming from GDA94 to GDA2020 ArcGIS has a default transformation GDA_1994_To_GDA2020_1 which doesn't match a GSB file in the
australia folder but may be a parameter only transformation. I am uncertain as to the accuracy of this transformation and so followed the instructions in this Esri support post about installing a new NTv2 file attempting to install the downloaded GSB file as the assumed to be more correct transformation between these datums.
Has anyone verified that the default Esri transformation is close enough (4th decimal place in MGA2020) to the ISCM GSB for all of Australia so that I don't need to jump through all these hoops on every workstation with ArcGIS installed?
Note: I understand that this isn't much of a question; I have posted this mostly as a resource for users who will be implementing GDA2020 after frustrating hours encountering numerous broken links and reading through verbose documents in a quest for a correct transformation and I'm hoping that this vague question saves others a considerable amount of time and frustration by posting the working links... at least until the data moves again and these links become broken too.