Remote sensing is the science and technology by which the properties of specified objects, area, or phenomenon can be identified, measured, and analyzed without direct contact with them in order to make useful decisions. The applications of remote sensing include land-use mapping, weather forecasting, environmental study, natural hazards study, and resource exploration.
Principle of Remote Sensing
The source of remote sensing data is the electromagnetic radiations which are emitted or reflected by the object, which then helps in their identification and classification.
Components of Remote Sensing
1. Platform
A Platform is defined as the carrier for remote sensing sensors. There are three major remote sensing platforms: ground-level platform (towers and cranes), aerial platforms (Helicopters, low altitude aircraft, high altitude aircraft), and spaceborne platforms (space shuttles, polar-orbiting satellites, and geostationary satellites).
2. Sensors
It is a device that receives electromagnetic radiations and converts it into a signal that can be recorded and displayed as either numerical data or an image.
Elements Involved in Remote Sensing
- Energy Source or Illumination (A)
- Radiation and the Atmosphere (B)
- Interaction with the Object (C)
- Recording of Energy by the Sensor (D)
- Transmission, Reception and Processing (E)
- Interpretation and Analysis (F)
- Application (G)
Types of Remote Sensing Systems
- Visual Remote Sensing System such as human visual system
- Optical Remote Sensing
- Infrared Remote Sensing
- Microwave Remote Sensing
- Radar Remote Sensing
- Satellite Remote Sensing
- Airborne Remote Sensing
- Acoustic and near-acoustic remote sensing
Basic Processes in Remote Sensing
- Data acquisition (energy propagation, platforms)
- Processing (conversion of energy pattern to images)
- Analysis (quantitative and qualitative analysis)
- Accuracy assessment (radiometric and geometric correction)
- Information distribution to users
Remote Sensing Applications
1. Land Use Mapping
Remote sensing data is useful in obtaining up-to-date land use pattern of large areas at any given time and also monitor changes that occur from time to time. It can be used for updating road maps, asphalt conditions, and wetland delineation. This information is used by regional planners and administrators to frame policy matters for all-round development of the region.
2. Weather Forecasting
Remote sensing is extensively used in India for weather forecasting. It is also used to warn people about impending cyclones.
3. Environmental Study
It can be used to study deforestation, degradation of fertile lands, pollution in atmosphere, desertification, eutrophication of large water bodies and oil spillage from oil tankers.
4. Study of Natural hazards
Remote sensing can be used to study damages caused by earthquakes, volcanoes, landslides, floods and melting of ice in polar regions. Many times remote sensing will be helpful to predict the occurrence of natural hazards.
5. Resource exploration
Remote sensing data is helpful for updating existing geological maps, rapid preparation of lineament and tectonic maps, identifying the sites for quarrying the minerals and helpful in locating fossil fuel deposits.