The science of remote sensing involves taking measurements of distant objects without actually touching the ones being studied. In a different sense, remote sensing is the process of gathering data and determining information about objects and materials (targets) that are situated on the surface of the earth or in its atmosphere. To do this, sensors (mostly multi-spectral) mounted on platforms placed far from the target are used to measure how the target interacts with electromagnetic radiation.
Pixels are arranged in rows (which run across) and columns (which run down) in raster data (also known as cells). Each pixel represents a specific geographic area, and its value corresponds to a characteristic of that area. Raster data can be obtained in one of two ways: either by converting vector data into a raster file, or by using satellite imagery, UAVs (drones), or airplanes to collect it. Remote sensing is the practice of gathering raster data from an aircraft or satellite (RS). These satellites or aircraft measure the radiation reflected and emitted radiation at a distance without making physical contact to detect and monitor the physical parameters of an area.