Geography (Introduction to Remote Sensing)
This Exam Covers the Following Topics
1. Introduction to Remote Sensing
- Definition of remote sensing
- The role of sensors and information-carrying energy waves
- Human eyes vs. remote sensing devices
2. Stages in Remote Sensing
- Source of energy (sun/self-emission)
- Transmission of energy from the source to the surface of the Earth
- Interaction of energy with Earth’s surface
- Propagation of reflected/emitted energy through the atmosphere
- Detection of reflected/emitted energy by the sensor
- Conversion of energy into photographic/digital form
- Extraction of information contents from data products
- Conversion of information into maps/tabular forms
3. Electromagnetic Radiation (EMR)
- Properties and propagation of EMR
- Electromagnetic spectrum: gamma rays, X-rays, ultraviolet rays, visible light, infrared rays, microwaves, and radio waves
- Use of different regions of the spectrum in remote sensing (visible, infrared, microwave)
4. Glossary of Key Terms
- Absorptance, Reflectance, Transmittance
- Spectral Bands (green, NIR, red, etc.)
- Digital Number (DN) in images
- Digital Image Processing (DIP)
- False Color Composite (FCC)
- Scene, Sensor, Image interpretation
5. Sensors
- Photographic (analog) vs. Non-photographic (digital) sensors
- Multispectral Scanners (MSS)
- Whiskbroom scanners
- Pushbroom scanners
- Spatial resolution, spectral resolution, and radiometric resolution of sensors
6. Remote Sensing Satellites
- Sun-synchronous satellites (e.g., IRS)
- Geostationary satellites (e.g., INSAT)
- Comparison between sun-synchronous and geostationary satellites
7. Multispectral Scanners
- Working principles of whiskbroom and pushbroom scanners
- Field of view (FOV), Instantaneous Field of View (IFOV), Total Field of View (TFOV)
- Digital Number (DN) and its relation to pixel intensity
8. Sensor Resolutions
- Spatial resolution: the smallest object detectable
- Spectral resolution: sensitivity to different wavelengths
- Radiometric resolution: ability to detect small energy differences
- Temporal resolution: time between successive images of the same area
9. Digital Image Processing
- Definition and process of converting digital images to information
- Elimination of errors in digital image data
- Interpretation and extraction of information from digital images
10. False Color Composite (FCC)
- Definition and creation of FCC images
- Assignment of false colors to spectral bands (e.g., blue, green, red)
- Use of FCC images to highlight vegetation, water bodies, and other natural features
11. Interpretation of Satellite Imageries
- Visual image interpretation methods
- Qualitative and quantitative analysis of terrain features
- Elements of visual interpretation:
- Tone or color
- Texture
- Shape
- Size
- Pattern
- Association of objects
12. Use of Remote Sensing for Environmental Monitoring
- Comparison of pre- and post-event images (e.g., tsunami impact, vegetation changes)
- Temporal analysis using satellite images for environmental and land use changes
- Applications in monitoring forests, agriculture, and urban areas
13. Data Products
- Photographic images vs. Digital images
- Conversion of digital numbers into brightness levels in images
- Reproduction of image details in different resolutions
14. Atmospheric Effects on Remote Sensing
- Absorption of energy by atmospheric gases (CO2, water vapor, etc.)
- Scattering of energy by dust particles and its effect on image brightness and color
- Modification of reflected/emitted energy as it travels through the atmosphere
15. Temporal Resolution
- Definition and importance of temporal resolution in tracking changes over time
- Use of temporal resolution to study environmental events such as deforestation, floods, etc.
16. Examples and Case Studies
- Interpretation of pre- and post-tsunami images
- Monitoring vegetation in the Himalayas using multispectral imaging
- Detection of turbid and clear water bodies using FCC images
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