This book provides the necessary background of geometry, mathematics and physical geodesy, useful to a rigorous approach to geodetic heights. The concept of height seems to be intuitive and immediate, but on the contrary it requires a good deal of scientific sharpness in the definition and use. As a matter of fact the geodetic, geographic and engineering practice has introduced many different heights to describe our Earth physical reality in terms of spatial position of points and surfaces. This has urged us to achieve a standard capability of transforming one system into the other. Often this is done in an approximate and clumsy way. This book solves the above practical problems in a rigorous way, showing what degree of approximation is used in approximate formulas. In addition the book gives a sound view on a matter that is presently occupying scientific associations, namely the unification of the global and regional height reference systems. It provides the mathematical background as well as the state of the art of its implementation. It will be particularly useful for professionals and national agencies.

This volume contains the proceedings of 24 peer-reviewed papers presented at the 3rd International Gravity Field Service (IGFS) General Assembly, which was organized by the International Gravity Field Service (IGFS), Commission 2 of the International Association of Geodesy (IAG), and Shanghai Astronomical Observatory (SHAO), Chinese Academy of Sciences. The Assembly was successfully held in Shanghai, China from June 30th to July 6th, 2014 with over 130 participants from 25 countries. The focus of the Assembly is on methods for observing, estimating and interpreting the Earth gravity field as well as its applications, including 6 sessions: gravimetry and gravity networks, global geopotential models and vertical datum unification, local geoid/gravity modelling, satellite gravimetry, mass movements in the Earth system and solid Earth investigations.