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NOAA Datums Videos 2014

Differential correction with NA2011 and the newest epoch of NAD83

See our and Datums Basics and GPS Tutorials for the long-awaited results of months of rigorous testing and peer review

Trimble Positions software has replaced Trimble GPS Analyst in ArcGIS 10.1

ALASKA GPS and GIS users - check out Joel Cusick's Datum and Projections presentation Feb 2013

ArcGIS 10.1 - New and Cool improvements see Presentation from Melita Kennedy, ESRI : Projections and Datums Dec 2012

Home Datums Basics Difference: WGS84 and NAD83
Difference: WGS84 and NAD83 PDF Print E-mail

Big shift

The original WGS84 and NAD83 were equivalent but this is no longer the case

Use HTDP to convert between WGS84 and NAD83

In the most current WGS84(G1130) versus NAD83(2011), NAD83(PA11), NAD83(MA11), shift between varies by location but is approximately 1.5 meters in static locations.  It is much larger in tectonically active areas.

These are differences reflect the following approximate velocities for the below areas....

Hawaii ~ 80 mm/yr

CA near San Andreas Fault ~ 50 mm/yr

South-Central Alaska ~40 mm/yr

Guam ~ 25 mm/yr

Puerto Rico and US Virgin Islands ~ 20 Mm/yr

Pacific  Northwest Coast ~ 15 mm/yr

Majority of the US ~ 1-2 mm/yr

nad83 wgs84 difference