NAD27 and NAD83 are examples of which type of datum?

NAD27 and NAD83 are examples of which type of datum?

• A. Geodetic datums
• B. Horizontal datums
• C. Tidal datums
• D. Vertical datums

Answer: (A)

These datums establish a reference surface and origin used to tie coordinates on the Earth to a mathematical model of its shape. NAD27 and NAD83 define different ellipsoids and anchor points, which changes how latitude and longitude are computed for any location. Because they specify the reference surface for horizontal positioning, they are geodetic datums. Tidal datums relate to sea level, and vertical datums relate to elevations or depths, so they’re not what these NAD datums represent. NAD27 uses an old ellipsoid (Clarke 1866), while NAD83 uses a more modern ellipsoid (GRS80) aligned with geocentric models.

These datums establish a reference surface and origin used to tie coordinates on the Earth to a mathematical model of its shape. NAD27 and NAD83 define different ellipsoids and anchor points, which changes how latitude and longitude are computed for any location. Because they specify the reference surface for horizontal positioning, they are geodetic datums. Tidal datums relate to sea level, and vertical datums relate to elevations or depths, so they’re not what these NAD datums represent. NAD27 uses an old ellipsoid (Clarke 1866), while NAD83 uses a more modern ellipsoid (GRS80) aligned with geocentric models.