Which spheroid is globally preferred for geographic measurements?

The preferred spheroid for global geographic measurements is the GRS80 (Geodetic Reference System 1980). This spheroid is significant because it is designed to provide a consistent and accurate framework for geographic coordinate systems used worldwide. The GRS80 model accounts for the irregular shape of the Earth by approximating it with a mathematically defined ellipsoid, which closely aligns with the mean sea level across the globe.

One of the key reasons for the widespread adoption of GRS80 is its integration into the North American Datum 1983 (NAD83), which provides a geocentric reference frame. This datum has become a standard because it offers greater precision for both horizontal and vertical positioning, making it ideal for applications in both mapping and navigation on a global scale.

Other spheroids mentioned, like WGS72 and NAD83, while relevant to specific applications, do not provide the same level of global consistency. The WGS72 is an earlier reference system, now largely replaced by WGS84, which is based on GRS80 but includes some additional adjustments for global positioning. IASP91 serves a more specialized purpose related to seismology and does not have the same level of application for general geographic measurements.

Thus, GRS80 is