https://business.esa.int/newcomers-earth-observation-guide
The aim of this guide is to help non-experts in providing a starting point in the decision process for selecting an appropriate Earth Observation (EO) solution. EO is defined as the process of acquiring observations of the Earth’s surface and atmosphere via remote sensing instruments. The acquired data is usually in the form of digital imagery. Earth’s surface can be observed from different platforms, each presenting its own advantages and limitations. Aerial platforms, for instance, generally provide the best resolutions and are very adjustable to the users’ needs, but the high cost of chartering a plane and paying the related manpower (pilots and technicians) restricts its use. Drones, also called Remotely Piloted Aircraft Systems (RPAS), are a fast-growing technology that tackles this cost problem, but regulations and their low carrying capacity currently limits their range of activity. On the other hand, satellites allow for reliable, true global coverage even above the most remote locations enabling regular repeat observations.