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NCAT vs ArcMap coordinate conversions

Question asked by jjohnson_washoe on Feb 22, 2019
Latest reply on Feb 22, 2019 by jjohnson_washoe

Our enterprise data (typical local gov datasets) is in NAD_1983_StatePlane_Nevada_West_FIPS_2703_Feet and datum=D_North_American_1983.  We have some new 3DEP lidar data that uses D_NAD_1983_2011, so I want to understand the differences between the two datums.

I've used the nifty NGS NCAT program to calculate the absolute XY shift between the two datums in our vicinity:NCAT coordinate conversion


My question is:  Why can't I get the same result in ArcMap?  


The transformation used above was automatically plugged in by ArcMap - I didn't select it.  Resulting coordinates in NAD1983_2011 are shown as X2 and Y2 below.

ArcMap projection coordinate result


One ASSUMPTION I've used is that ESRI's D_North_American_1983 means NAD1983(1986); that isn't explicitly stated anywhere I've seen.  What am I missing here?