It is the acquisition of information about an object or phenomenon without making physical contact with the object

1. Remote Sensing
MASHHOOD ARIF

2. Contents
 Definition
 Types of Remote Sensing
 Elements involved in Remote
Sensing
 Process of Remote Sensing
 Sensors
 Usual Platforms
 Interaction with Atmosphere
 Remote Sensing & GIS
Aerial Remote Sensing
Image Processing in Remote Sensing
Types of Resolution
Correction
Advantages & Disadvantages of
Remote Sensing
Applications
Conclusion

3. DEFINITION
It is the acquisition of information about an object or
phenomenon without making physical contact with the object
In modern usage, the term generally refers to the use of aerial
sensor technologies to detect and classify objects on Earth by
means of propagated signals

4. TYPES (on basis of energy)
Active Remote Sensing
(artificial energy source)
Passive Remote Sensing
(natural energy source)

6. TYPES (on basis of range of electromagnetic radiation)
 Optical Remote Sensing
(wavelength range 300nm-3000nm)
 Thermal Remote Sensing
(wavelength range 3000-14000nm)
 Microwave Remote Sensing
(wavelength range 1mm-1m)

7. ELEMENTS INVOLVED IN REMOTE SENSING
Source of energy
Radiation and the atmosphere
Interaction with object
Recording of energy by sensor
Transmission, reception and processing
Interpretation and analysis
Application

8. PROCESS OF REMOTE SENSING
Data acquisition
Processing
Analysis
Accuracy assessment
Information distribution to users

9. SENSORS
Imaging Sensors
Sensors which provide output to create image
Example: LISS I, LISS II, LISS III, etc (Linear Imaging Self Scanning Sensor LISS)
Non-imaging Sensors
Sensors which provide numerical output with respect to quantum of radiation
Example: Radiometer, Scatterometer, etc

10. USUAL PLATFORMS
AIRCRAFT
 Helicopters
 Microlites
 Low altitude aircrafts
 High altitude aircrafts
SATELLITE
 Orbiting satellites
 Geostationary satellites

11. INTERACTION WITH THE ATMOSPHERE
Radiation used for remote sensing has to travel through Earth’s
atmosphere
Particles and gases in the atmosphere can affect it
These effects are caused by mechanisms of scattering and
absorption

12. Remote Sensing & GIS
 The science of acquiring information about the Earth using remote
instruments, such as satellites
 It is inherently useful for disaster management
 Satellites offer accurate, frequent and almost instantaneous data
over large areas anywhere in the world
 When a disaster strikes, remote sensing is often the only way to
view what is happening on the ground

13. Remote Sensing & GIS (Contd..)
Energy Source or Illumination (A)
Radiation and the Atmosphere (B)
Interaction with the Target (C)
Recording of Energy by the Sensor (D)
Transmission, Reception, and Processing (E)
Interpretation and Analysis (F)
Application (G)

14. Aerial Remote Sensing
Aerial Remote Sensing Aerial photography is the most commonly
used form of remote sensing and is widely used for topographic
mapping, surveys for geological, soil and forestry mapping,
engineering, town planning and environmental surveys on larger
scale

15. IMAGE PROCESSING IN REMOTE SENSING
 Input data
 Reconstruction/ correction
 Transformation
 Classification
 Output

16. TYPES OF RESOLUTION
Spatial Resolution
The size of a pixel that is recorded in a raster image
Spectral Resolution
The wavelength width of the different frequency bands recorded
Radiometric Resolution
The number of different intensities of radiation the sensor is able to distinguish
Temporal Resolution
The frequency of flyovers by the satellite or plane

17. CORRECTION
Radiometric correction
Gives a scale to the pixel values
Topographic correction
In rugged mountains, as a result of terrain, the effective illumination
of pixels varies considerably. The purpose of topographic correction
is to eliminate this effect
Atmospheric correction
Elimination of atmospheric haze by rescaling each frequency band

18. ADVANTAGES OF REMOTE SENSING
 Real time
 Spatial locations and extent of features can be corrected accurately
 Cheaper
 Faster
 Different scales
 Easy updation
 More analytical themes
 Remote sensors "see" over a broader portion of the spectrum than the
human eye

19. DISADVANTAGES OF REMOTE SENSING
 Expensive to build and operate
 Measurement uncertainty can be large
 Data interpretation can be difficult

20. APPLICATIONS OF REMOTE SENSING
 Conventional radar is mostly associated with aerial traffic control,
early warning, and certain large scale meteorological data
 Altimeters measure wind speeds and direction, and surface ocean
currents and directions
 Light detection and ranging (LIDAR) is well known in examples of
weapon ranging, laser illuminated homing of projectiles
 Radiometers and photometers are the most common instrument in
use, collecting reflected and emitted radiation in a wide range of
frequencies

21. RADAR LIDAR

22. APPLICATIONS OF REMOTE SENSING (Contd..)
 Stereographic pairs of aerial photographs have often been used to
make topographic maps
 Hyperspectral imagers are used in various applications including
mineralogy, biology, defense, and environmental measurements
 remote sensing allows to follow-up and monitor risk areas in the
long term, to determine desertification factors

24. Conclusion
 Remote Sensing and GIS technology is very effective tool for
suggesting action plans /management strategies for various
disciplines
 The technique of obtaining information about objects through the
analysis of data collected by special instruments that are not in
physical contact with the objects of investigation