*25.09.2011*
*"Geodesy is the science of the measurement and mapping of the earth's
surface"* F. R. Helmert,
1880*.*

*"The problem of geodesy is to determine the **figure**
and the external gravity field of the earth and of
other celestial bodies as functions of time; as well as, to determine the mean earth **ellipsoid**
from
parameters observed on and exterior to the earth's surface [Torge 1991 p.2]." *
Geodesy is devided into three areas *[Torge 1991, p.1]*:

*global
geodesy* includes the determination of the shape and size of the earth, it's orientation in
space, and it's external gravity field
*geodetic
surveys* (national and supranational) is for the determination of the earth's surface and
gravity field over a region that typically spans a country or a group of countries. The earth's
curvature and gravity field must be considered.
*plane
surveying* (topographic surveying, cadastral surveying, engineering surveying): the details
of the earth's surface are determindes in a local level, and thus curvature and gravity effects are
generally ignored.