Earth observation

Earth observation (EO) is the gathering of information about the physical, chemical, and biological systems of the planet Earth. It can be performed via remote-sensing technologies (Earth observation satellites) or through direct-contact sensors in ground-based or airborne platforms (such as weather stations and weather balloons, for example).

According to the Group on Earth Observations (GEO), the concept encompasses both "space-based or remotely-sensed data, as well as ground-based or in situ data". Earth observation is used to monitor and assess the status of and changes in natural and built environments.