Sunday, January 25, 2015

Geodesy and Geodetic Methods

What is Geodesy? 
Due to technology, the knowledge of Earth's shape and landscapes has changed over the years. Thanks to geodesy, studying these changes has become easier and more precise. Geodesy focuses on Earth's size, orientation, shape, and gravitational field as well as fluctuations in these values.

Modern Geodesy
Advances in modern technologies, such as GPS and synthetic aperture radar satellites, have allowed geodetic research to become even more precise. Modern geodesy gathers information using four basic techniques: positioning of geodetic instruments, altimetry, interferometric synthetic aperture radar (InSAR), and gravity studies. Efficient positioning of radio telescopes, satellite lasers, and GPS is necessary for precise geodetic measurements. Altimetry measurements gather data through changes in elevation instead of measuring 3D changes by alternative positioning techniques. Altimetry satellites shoot pulses at Earth's surface in order to gain ground measurements. InSAR uses SAR observations to produce digital elevation models. Gravity studies use satellite orbits to measure gravitational changes because satellite orbits are very sensitive to gravitational changes which makes them useful when determining the shape of the Earth. 

Applications (Global/Local) and Societal Implications

Geodesy can be used on a global scale to calculate global issues such as water budgets for each country. 
Using satellites to measure sea levels helps determine these figures. 

The same research methods can be applied on a local scale.Pictured above shows the use of geodetic 
tools to gather information about river and lake water levels in the Congo. This helps give insight 
into available ground water. 

As a result of these technological advances and their implementations, people can be better informed about the societal impacts of small changes in Earth's environment. For example, the severity of hazards that pose threats to coastal regions, such as flooding due to rising sea levels, can be measured more accurately using geodetic methods. The precision of geodetic measurements and the variety of applications for geodetic data make geodesy make it essential for understanding further many of the Earth's processes and humanity's impact on those processes. 

Wdowinski, S., & Eriksson, S. (n.d.). Geodesy in the 21st Century. Eos, Transactions American Geophysical Union, 153-153.


  1. Effective blogging. The information provided previous to the research summary allows for readers to maintain a level of interest while being able to follow along with terms.

  2. The last map was of Central African water levels. Can this be used to warn local populations of likely flood areas? Has this been used on the local level?

  3. In reference to the gravity studies where the satellite orbits are used to determine the shape of the Earth, would the Moon have much of an effect on the satellite itself? Tides are caused by the Moon orbiting the Earth, so it's surely powerful enough to affect a satellite, right? If so, I wonder how scientists factor out this so-called "Moon-interference" from their data.