I. Curvature and Refraction

1. What

The fundamental difference between plane and geodetic surveying is the latter takes into account the size and shape of the earth. However, there is no distinct point where surveying crosses from one classification to the other; there tends to be a gray area in between. This is because much of the technology we use today allows us to measure over larger areas than just a few decades ago.

Earth curvature and atmospheric refraction are two primary errors that must be taken into account when measurements become sufficiently long. Curvature and refraction affect any measurements dependent on an optical line of sight (LoS) or energy wave, which covers a lot of survey measuremetns. Because of this, we'll discuss them here and then refer back to this material in later topics.