Geodesy is the science of extremely accurate measurements of Earth’s shape, gravity, and orientation—everything from the coordinate system that underlies all navigation and positioning to detecting the warning signs of a volcanic eruption. You may not have heard of the term “geodesy” before, but you’ve definitely benefited from it.

The tools of geodesy let us measure moving tectonic plates, rising sea level, shrinking glaciers, soil erosion after a wildfire, or groundwater overuse during a drought. Increasingly, they’re also being used for emerging applications like autonomous vehicles and precision agriculture.

Instruments that measure very precise positions using GPS satellites (or multiple satellite networks, more generally termed GNSS for “Global Navigation Satellite System”) are among those tools. There are also satellites that can measure tiny surface changes, like InSAR (Interferometric Synthetic Aperture Radar) satellites. And lidar devices on the ground or in the air use lasers to generate 3D imagery that also quantifies small changes over time. These are just some of the technologies that geodesists use to study our dynamic planet.

mountain slope with lidar data overlaid
Terrestrial laser scanning data overlaid on an image of the Flatirons near Boulder, Colorado.

This section of our website is meant to help you learn more about these technologies and applications. At the bottom of each page, you’ll find links to dive deeper or explore related topics.

As the operator of the NSF’s Geodetic Facility for the Advancement of Geoscience (GAGE) Facility, UNAVCO supports geodesy by running instrument networks like the Network of the Americas, providing equipment and support for projects, and through data access and archiving, technical short courses, educational resources, and internship programs.


More Resources


What is Geodesy?


Geodesy Lessons


Space Geodesy Project


Geodetic Projects

GPS Spotlight

How GPS Works