Remote sensing is the scientific method of detecting and monitoring the physical properties of an area by calculating its emitted and reflected radiation at a distance (generally from an aircraft or satellite). It is the accumulation of information about a phenomenon or objects without having physical contact with the targeted objects. It is especially applied to gather details about the Earth and other solar planets.
Remote sensing is applied to gather details about the Earth and other solar planets. Remote sensing is employed in various fields, including ecology, hydrology, geology, meteorology, geography, oceanography, glaciology, etc. It has also been applied in intelligence, economic, planning, and military fields.
The present-day form of remote sensing evolved with the development of aerial flight. One of the earliest proponents of aerial photography was balloonist G. Tournachon. He produced images while flying in his balloon. Kits, unmanned balloons, and rockets were used for making remote images in the early stages.
Active remote sensing uses a man-made source of radiation as the inspecting medium. The resulting signal disperses back to the sensor and characterises the Earth or the atmosphere. LiDAR and RADAR are the two main examples of active remote sensing. Both emit radiation beams from a sensor and calculate the scattered radiation that has returned to the sensor.
Passive remote sensing depends on solar radiation as the source of illumination. Hyperspectral and multispectral sensors are the main ones that use this type of remote sensing. It generally focuses on shortwave infrared, visible, and near-infrared spectral regions.
Tracking and analysis of clouds can be done through remote sensing. It allows meteorologists to predict and observe weather patterns, volcanic eruptions, sea movements, etc.
Remote sensing is extensively used in detecting and mapping ocean floor topography. Hidden underwater deep canyons, mountain ranges and magnetic activities can be easily detected and analysed using remotely sensed images.
The value of a GIS comes when you are able to answer questions related to location, patterns, and conditions
Not exactly. It contains maps or better can create maps. Think GIS as a set of systems and services that help you store, analyze, process and share geolocated data
Quite a starter question. GIS stands for Geographic Information Systems. To put it in a more strict definition, GIS is a system of computer software, hardware, data, procedures and personnel combined to help, manipulate, analyze, and present information that is tied to a geographic location.