The NGS GEOID Page

First created 3/01/2000. DAS.

Last updated 12/24/2003. DAS.

What is the geoid?

(Definition, History)

What is a deflection
of the vertical?
under construction

(Definition, History)

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

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



The latest models: GEOID03, USGG2003, GEOID99, G99SSS , G99BMunder construction , and DEFLEC99




Comparison of the latest models with other geoid models under construction


Geoid Links

(Agencies, Models)

Research Links

(Projects at least loosely tied to the geoid)

Ongoing geoid research projects at NGSunder construction

(Papers in review, currently unpublished research topics)

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

Got a question?

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