Geodesy is the scientific discipline that studies the size, shape and location of fixed points on the Earth. At one time, all work done in the field of geodesy was based on land surveys. Now, land surveys are done in conjunction with the use of satellites. The field of geodesy also includes the study of tides as well as crustal and polar motion. The field of geodesy developed from the human need to understand the world in which we live. As it was once believed that our world was flat, we now know much more about our planet through specialized fields such as geodesy.