The NGS GEOID Page

What is the geoid?

(Definition, History)

What is a deflection
of the vertical?

(Definition, History)

geoid and deflection models has NGS made in the last decade?

(Updated 1/4/2001 to include the 1990-1994 models)

GRAV-D

Comparison of the latest models with other geoid models

Geoid Links

(Agencies, Models)

Research Links

(Projects at least loosely tied to the geoid)

North American Geoid

International Association of Geodesy Commission Project 2.2

Online papers about the geoid

Who uses the geoid?

(Studies with NGS geoid models)

NGS geoid research software

Online slideshow presentations

Absolute Gravimeter

Cryogenic Gravimeter