WGS84 vs NAD83
WGS84 and NAD83 are datums that define the shape and size of the Earth. Datums are used to match the location of features and locations on a map. Different datums have been used in different times – each of them changing as per the view of the Earth. WGS84 is the World Geodetic System of 1984, and NAD83 is The North American 1983 datum.
The World Geodetic System of 1984 and the North American 1983 datums were considered the same from 1986 to 1994. Both these datums were based on similar Doppler reference frames.
NAD83 can also be termed as the horizontal control datum that is used for the U.S., Canada, Central America, and Mexico. A new datum, the NAD83 is based on an adjustment of 250,000 points which includes 600 Satellite Doppler stations.
WGS84 is used by the U.S. Department of Defense. The National Geospatial-Intelligence Agency, which was formerly called the National Imagery and Mapping Agency, or the Defense Mapping Agency used the WGS84 datum. This WGS84 datum came into force in 1987 that used the technique of Doppler satellite surveying.
One of the main differences that can be seen between WGS84 and NAD83 is in the ellipsoid. The NAD83 uses the Geodetic Reference System ellipsoid, and the WGS84 uses the WGS84 ellipsoid. The ellipsoid of WGS84’s is 0.21 mm longer than the ellipsoid of NAD83.
The World Geodetic System of 1984 datum has shifted 100 meters from the earlier used prime meridian. But The North American 1983 datum has not shifted from its earlier location.
Summary:
1.WGS84 and NAD83 are datums that define the shape and size of the Earth.
2.WGS84 is the World Geodetic System of 1984, and NAD83 is the North American 1983 datum.
3.NAD83 is used for the U.S., Canada, Central America, and Mexico. WGS84 is used by the U.S. Department of Defense.
4.The NAD83 uses the Geodetic Reference System ellipsoid, and the WGS84 uses the WGS84 ellipsoid. The ellipsoid of WGS84’s is 0.21 mm longer than the ellipsoid of NAD83.
5.The World Geodetic System of 1984 and the North American 1983 datums were considered then same from 1986 to 1994.
6.The World Geodetic System of 1984 datum has shifted 100 meters from the earlier used prime meridian. But The 7.North American 1983 datum has not shifted from its earlier location.
8.NAD83 is based on adjustment of 250,000 points which includes 600 Satellite Doppler stations.