The United States Geological Survey (USGS) developed the World Geodetic System 1984 (WGS84) to provide a global coordinate system for geodesy. The North American Datum 1983 (NAD83) is based on WGS84, but with a few modifications to improve its accuracy for surveying in North America. There are slight differences between the two systems, which can cause mapping and surveying errors if not accounted for. This article explains the differences between WGS84 and NAD83 and how to properly account for them.
What is WGS84?
WGS84 is the standard geographic coordinate system used by the GPS. WGS84 stands for World Geodetic System of 1984. The WGS84 ellipsoid is used as the reference surface for whole earth measurements. The WGS84 datum is based on a global WGS84 ellipsoid with defined geoid undulation set to zero. WGS84 is accurate to within about 1 meter. The WGS84 datum was established in 1984 and has been updated several times since then. In 2020, the WGS 84 epoch was 2010.0. The WGS 84 datum will continue to be updated as new Earth observations are made.
What is NAD83?
NAD83 is the standard geographic coordinate system used in North America. NAD83 is based on the GRS80 ellipsoid, and its latitude and longitude coordinates are measured in decimal degrees. NAD83 is typically used for large-scale mapping projects, such as those involving topographic data. In addition, NAD83 is the datum of choice for GPS applications in North America. NAD83 has been updated several times since it was first introduced, and the most recent update (NAD83(2011)) was released in 2011. The next update is scheduled for 2025.
Difference between WGS84 and NAD83
WGS84 (World Geodetic System 1984) and NAD83 (North American Datum of 1983) are two common geodetic datums. WGS84 is based on the ellipsoid, whereas NAD83 is based on the geoid. WGS84 is used by GPS systems, and NAD83 is used by maps in North America. WGS84 is more accurate than NAD83, but NAD83 is more widely used.
Conclusion
The difference between WGS84 and NAD83 can be confusing for people who are not familiar with coordinate systems. However, it is important to understand the differences so that you can use the correct coordinates when mapping or surveying your data. We hope this article has helped clarify some of the differences between these two coordinate systems.
