Remote sensing is a process that involves the collection of information about an object or phenomenon without physical contact, done from a distance often using satellite or aerial platforms.
1. Sensor: Device or instrument used to collect data, eg cameras, spectrometers, radar systems etc.
2. Platform: Which vehicle carries the sensor for example satellites, aircrafts, drones etc.
3. Data Transmission: The movements of collected data from the sensor to the ground stations for further analysis.
Types of Remote Sensing:
1. Passive Remote Sensing:
This relies on external sources of radiation such as sunlight and measures reflected or emitted energy (eg optical sensors capturing visible light).
2. Active Remote Sensing:
It uses its own energy source like radar and measures the reflected signal (useful in cloudy conditions and for mapping topography).
One must understand the electromagnetic spectrum to study remote sensing. It includes various forms of energy like radio waves, microwaves, infrared, visible light, ultraviolet rays, x-rays and gamma rays.
- Environmental Monitoring: Tracking deforestation; land use changes; monitoring ecosystems.
- Agriculture: To access crop health; monitor irrigation; predict yields.
- Urban Planning: Analyzing urban growth; infrastructure development; land-use planning.
- Disaster Management: Assessing impact of natural disasters e.g earthquakes; floods; wildfires.
- Spatial: Level of detail in the image.
- Spectral: Number and size of spectral bands in the sensor.
- Temporal: time interval between image acquisitions
2. Enhancement Techniques:
- Image enhancement improves visualization e.g contrast stretching or histogram equalization
1. Cloud Cover:
It limits visibility in optical sensors
Radar and microwave sensors are less affected
Some applications may be prohibitive due to satellite and sensor costs
3. Data Interpretation:
It requires expertise in image analysis and interpretation