2.1 Ground, Air and Space 2.2 Orbits and Swaths 2.3 Spatial Resolution 2.4 Spectral Characteristics 2.5 Radiometeric Resolution 2.6 Temporal Resolution 2.7 Cameras and Aerial Photography 2.8 Multispectral Scanning 2.9 Thermal Imaging 2.10 Geometric Distortion 2.11 Weather Sensors 2.12 Land Observation Sensors 2.13 Marine Observation Sensors 2.14 Other Sensors 2.15 Data Reception, Transmission and Processing 2.16 Endnotes