Geodesy for the layman
This text is taken from chapter 1 of the public domain resource Geodesy for the Layman at http://www.ngs.noaa.gov/PUBS_LIB/Geodesy4Layman/TR80003A.HTM#ZZ0 -- please Wikify as necessary.
What is geodesy? Webster defines geodesy as "that branch of applied mathematics which determines by observation and measurement the exact positions of points and the figures and areas of large portions of the earth's surface, the shape and size of the earth, and the variations of terrestrial gravity." It is a specialized application of several familiar facets of basic mathematical and physical concepts. In practice, geodesy uses the principles of mathematics, astronomy and physics, and applies them within the capabilities of modern engineering and technology.
In the past, military geodesy was largely involved with the practical aspect of the determination of exact positions of points on the earth's surface for mapping or artillery control purposes. The determination of the precise size and shape of the earth had a purely scientific role. Modern requirements are for answers to problems in satellite tracking, global navigation and defensive missile operations.
I History of Geodesy
II Figure of the Earth
III Geodetic Surveying Techniques
IV Geodetic Systems
V Physical Geodesy (see also existing Wikipedia article physical geodesy)
VI Satellite Geodesy
VII Other Developments in Geodesy
VIII The World Geodetic System