Remote Sensing
Remote Sensing encompasses a range of technologies and tools which capture/analyze the energy that is reflected from Earth. Sensors are mounted either on satellites or aircraft, and can be passive (capturing energy that is naturally available; e.g. satellite-based optical sensors) or active (providing their own energy for illumination, then detecting and measuring the reflected energy; e.g. Synthetic Aperture Radar / SAR and Light Detection and Ranging / LiDAR).