Gravity is an important part of geodesy, with implications for height measurements and many other applications. In this module, we explore the concept of equipotential surfaces and relate them to gravity. Then we discuss geodetic applications that rely on accurate gravity measurements, including leveling surveys and floodplain mapping. We introduce a special surface based on gravity, called the gravimetric geoid, and explain why we want to use it as a reference datum. We discuss how to measure Earth’s gravity and introduce you to the National Geodetic Survey’s GRAV-D project, including how and why the U.S. and a number of other countries plan to use a gravity-based vertical datum.
In order to better serve our users and sponsors, access to our online materials requires registration. To learn more about registering or to get help with common questions about our site, please visit our FAQs.
Most of the material made available on MetEd is free for non-commercial, educational use. We encourage you to use our material to enhance your education and training efforts. To review the legal-speak with all the nitty gritty details, see our Legal Notices page.