GEODESY … where on earth are we?


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Table of Contents

GEODESY … where on earth are we?

What is Geodesy?

Earth-Centered, Earth Fixed (ECEF System)

What shape is the earth’s surface? (Geoid)

ELLIPSOID (ellipse rotated about the semi-minor (polar) axis

What help is a Geodesist?

Horizontal Datum Plane (HDP)

Coordinate System Comparison



Horizontal datum

DATUM - the working surface

DATUM - different ellipsoids

What is a Projection

So What … I can see where I am

Some History of the Datums

Regional Datums are not Global

Further Evolution of Datums

World Geodetic System 1984

Comparison of ellipsoids

Approximate Difference between NAD27 and NAD83 at LPSRC

Glossary Review

Author: Dr. D Briggs