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What version of WGS84 is in ArcGIS

Question asked by fallingdog Champion on May 2, 2017
Latest reply on Jul 20, 2017 by MKennedy-esristaff

I am wondering about WGS84 as we move through time.


My understanding is that any given spot on the earth's surface latitude and longitude will change over time in this system. There are two sources of change:


1) NGA (National Geospatial-Intelligence Agency) will periodically shift the center of the WGS84 ellipsoid to better align with their current best guess for the center of the earth's mass (I think they are using a geoid to find the center of mass). At which time the will release a new version of the WGS84 and note the GPS weeks in the name, e.g. WGS84 (G1150).


2) WGS84 is not locked to any land mass but to the stars. So, as the tectonic plates drift around on the earth's mantle a location on the earth's surfaces can change over time.


Does that sound right?


So, when I select WGS84 as my GCS what version of WGS84 am I getting?


WGS84 (G873)
WGS84 (G1150)
WGS84 (G1674)
WGS84 (G1762)

Something else?