A geodetic datum is a reference framework used to measure and represent the Earth's surface. It defines the size and shape of the Earth, as well as the coordinate system for locating points on the Earth's surface. Common examples include the WGS 84 datum, which is widely used in GPS technology, and the NAD83 datum, used in North America. Geodetic datums are essential for mapping, navigation, and various scientific applications. They help ensure that geographic data is consistent and accurate across different regions. By providing a common reference, geodetic datums facilitate communication and data sharing among various disciplines and technologies.