![Earth and Moon](https://www.astronomy.com/wp-content/uploads/sites/2/2023/02/asy-20000927-00016-orig-lg.jpg)
This image shows a partial view of Earth as well as the Moon in the background.
JPL/NASA
Elsewhere in the solar system, where there are no standing bodies of water, we normally use the planet or moon’s average radius as a reference for measuring elevation.