NAD is the abbreviation used for North American Datum, which is the official geodetic datum common in North America. NAD 1927, or NAD 27, and NAD 1983, or NAD 83, are two types of datum used in North America, and they differ in measurement from one another. To understand the difference between the two in depth, read further.


NAD 27

The North American Datum 27 was based on Clarke Ellipsoid’s measurement, which is based on the manual graphing of the entire continent. This datum is the official system used in the continent by cartographers and satellite navigation system for translating the position of their object to their actual position on Earth. NAD 27 is based on the longitude and latitude of the globe and also, the direction between the two points. It involves the horizontal datum of the continent, and it is dependent on the traditional positioning technology.


NAD 83

The North American Datum 83’s foundation was based on the Geodetic Reference System (GRS) of 1980. This dealt with the estimated measurement of the earth as a whole. This system is prevalent in America and it deals with the approximate measure of the planet. Furthermore, it covers the horizontal control for North America, Canada, Mexico, and Central America. NAD 83 is an earth-centered datum, and so, it has no direction of preliminary point. It is more accurate than other systems, as it supports the three-dimensional capabilities of modern positioning system.