NAD83(2011) epoch 2010.0 vs WGS84(G1762) Offset

Technical Summary: Highly technical analysis of the 1 to 2 meter datum shift between the current US standard survey datum and the global satellite navigation datum.
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Using the wrong datum or applying coordinates without grid-to-ground correction can cause 1–400 metre positional errors — a leading cause of surveying negligence claims and contract disputes.

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While early versions of NAD83 and WGS84 (in 1986/1987) were virtually identical, they have diverged significantly. The North American Plate moves relative to the global reference frame. Because NAD83 is 'plate-fixed', coordinates on the ground remain relatively stable over time. WGS84, being a dynamic global frame, moves with the earth's general rotation and plate mechanics.

The Current realization: G1762

If you take a raw RTK GPS shot today (which resolves natively to WGS84 or an ITRF equivalent) and plot it natively in a CAD system expecting NAD83(2011), the point will be shifted roughly 1-2 meters. Official NGS transformation tools must be used to execute a 14-parameter Helmert transformation to shift the time-dependent WGS84 coordinates into the fixed NAD83 frame.

Frequently Asked Technical Questions

Are WGS84 and NAD83 the same?

No. While they were functionally equivalent in 1986, tectonic drift has caused them to separate by 1 to 2 meters in the continental US today. They must be mathematically transformed for engineering work.