* Determining the Earth's figure: This means understanding the overall shape of the Earth, which isn't perfectly spherical but rather an oblate spheroid (slightly flattened at the poles and bulging at the equator).

* Measuring the Earth's gravity: This includes the strength and direction of gravity at different locations on Earth.

* Mapping the Earth's surface: This encompasses creating precise models of the Earth's surface and its features, such as mountains, valleys, and oceans.

* Studying the Earth's rotation: Geodesy plays a role in understanding the Earth's rotation and how it affects other aspects of the planet, such as the position of the poles.

Here's a breakdown of what geodesy specifically measures:

* Geodetic coordinates: This includes latitude, longitude, and elevation, which are essential for precise location determination.

* Earth's gravity field: Geodesists measure the gravitational potential and acceleration at different points on the Earth's surface.

* Earth's rotation: Geodesy helps determine the Earth's rotation speed, the length of day, and the orientation of the rotation axis.

* Tectonic plate motion: Geodesy provides crucial data for understanding the movement of Earth's tectonic plates.

* Sea level change: Geodesy monitors changes in sea level, contributing to our understanding of climate change.

In essence, geodesy is the foundation for accurate mapping, navigation, and understanding the dynamics of our planet. It plays a vital role in fields such as surveying, cartography, space science, and natural hazard monitoring.