The scope of this university course is to give a board overview of the technical issues and major topics dealt with in earth observation. It serves as an introduction to more specialised courses in remote sensing and photogrammetry. After highlighting some global megatrends that can be expected to spur the demand for earth observation data in the 21th Century, a short recap of some basic physical concepts is provided. A historical approach is chosen for explaining some scientific and technological developments that have strongly shaped the field of earth observation. The different elements of the earth observation process, namely the sensor systems, the data processing in the ¿ground segment¿ and the use of the processed data in applications, are discussed in detail. The course closes with a discussion of some recent trends that may strongly shape the developments of earth observation in the years to come.
