Good morning,

I will try to make this as understandable as possible:

Objective:  To show why proper metadata (datum/realization wise) is important.

I got the datasheet for a geodetic control point in NJ.  It has a current NAD 83(2011) lat/lon.  It also has many superseded coordinates (Lat/Lon) going all the way back to NAD 83(1986).

I created a map in ArcMap, and established the data frame coordinate reference to be NAD 83(2011)

I then created a .txt file of the various NAD 83 positions that reflected the various realizations 2011, 2007, 1996, 1992, 1986.

I added the xy data to the map and told ArcMap that they were Geographic NAD 83 (2011) (which of course they were not).  As one would expect, I got 5 dots on the map with a spatial separation that reflected the differences between the 5 realizations.

Next I created one file for each coordinate, and added each file one at a time.  This time, I told ArcMap that the coordinate system for each file was actual realization of the position, i.e., when adding the NAD 83(2007) lat and lon, I told ArcMap that the coordinate system of the position was in fact NAD 83(2007).  The result was 5 dots that plotted exactly on top of the other 5 dots, i.e., no transformation took place?

Am I doing something wrong?