When mapping property boundaries or executing construction stakes, surveyors often face a critical question: should I use NAD83 or WGS84?
The Numeric Shift
According to the National Geodetic Survey (NGS) and leading academic sources, the difference between the modern realizations is roughly 1 to 2 meters (3.28 to 6.56 feet). This difference is largely driven by the drifting of the North American tectonic plate, which WGS84 tracks dynamically but NAD83 holds fixed relative to the continent.
Why 3 to 6 Feet Matters
A 3-foot error in a property line or building foundation is catastrophic in construction (where tolerances are generally ±0.10 feet). Therefore, treating GPS-derived WGS84 coordinates as equivalent to NAD83 State Plane coordinates without proper EPSG transformations will virtually guarantee a 1-2m layout error.