"Remote sensing is the science (and to some extent, art) of acquiring information about the Earth's surface without actually being in contact with it. This is done by sensing and recording reflected or emitted energy and processing, analyzing, and applying that information".
Remote Sensing, process of obtaining information about land, water, or an object, without any physical contact between the sensor and the subject of analysis. The term remote sensing most often refers to the collection of data by instruments carried aboard aircraft or satellites. Remote sensing systems are commonly used to survey, map, and monitor the resources and environment of Earth. They also have been used to explore other planets.
There are several different types of remote sensing devices. Many systems take photographs with cameras, recording reflected energy in the visible spectrum. Other systems record electromagnetic energy beyond the range of human sight, such as infrared radiation and microwaves. Multispectral scanners produce images across both the visible and the infrared spectrum.
Remote sensing is changing rapidly. Some satellites carry instruments that can provide images of objects as small as an automobile and constantly improving technology promises even better resolution in the near future. Computer-assisted image-analysis techniques are leading to many new applications for remote sensing.