Geoid globe

Geoid height globe of the EIGEN-6C4 model by Foerste et al.

"The Geoid" is a theoretical surface which represents the shape that the ocean surface would have due to the earths gravitational field, and its extension onto land, relative to a reference ellipsoid.

It provides geophysicists with information about the density structure of the earth - where there is a high density anomaly, gravity is slightly stronger and pulls the water towards it which creates a bulge at the surface - a "geoid high". Geoid topography is generally in the range of ±100m.

The model here has a vertical exaggeration of approximately 12,000. A step of ~1 mm has been added at the coastline to aid visual interpretation of location in areas with extensive continental shelves. No other source of topography has been added - the resemblance to actual surface topography reflects that mountains are much more dense than the air around them!

The underlying data, along with many other global determination