Remote sensing involves obtaining information about objects without physical contact. It uses electromagnetic radiation to detect and classify features on Earth's surface. The key components of remote sensing are an energy source, sensors to record radiation, and data analysis. There are two main types - passive sensors that detect sunlight reflected by Earth and active sensors that emit and detect radiation such as radar. Spectral bands divide the electromagnetic spectrum into groupings like visible, infrared, and microwave used by different sensors. Remote sensing has many applications including mapping agriculture, forestry, geology, fisheries, and monitoring the environment.

1. Remote Sensing And Its
Application
By-Binita Yadav

2. CONTENT:
• Remote sensing
• Basic components of Remote Sensing
• Types of Remote Sensing
• Spectral Bands
• GIS
• Application of Remote Sensing
• References

3. What is Remote Sensing?
Remote sensing is the securing of data about an object or
phenomenon without connecting with the object. Remote sensing is
utilized in various fields like topography, hydrology, environment,
oceanography and many more.
Conventionally remote sensing deals with the usenof light, i.e.,
electromagnetic radiation as the medium of interactions. RS refers
to the identification of earth features by detecting the characterist-
ics electromagnetic radiation that is reflected from the earth’s
surface.

4. Basic Components of Remote Sensing
• Energy source or Illumination: It is the first requirements of
remote sensing. It illuminates or provides electromagnetic energy
to the target of interest.
• Radiation and the Atmosphere: As the energy travels from its
source to the target, it will come in contact with and interact
with the atmosphere it passes through. This interaction may take
place a second time as the energy travels from the target to the
sensor.
• Interaction with the Target: Once the energy makes its way to the
target through the atmosphere, it interacts with the target
depending on the properties of both the target and the radiation.

5. • Recording of Energy by the sensor: After the energy has been
scattered by or emitted from the target, a sensor is required to
collect and record the electromagnetic radiation.
• Transmission, Reception, and Processing: The energy recorded by
the sensor has to be transmitted, often in electronic form,to a
receiving and processing station where the data are processed into
an image.
• Interpretation and Analysis: The processed image is interpreted,
visually and or digitally or electronically to extract information
about the target which was illuminated.
• Application: The final element of the remote sensing process is
achieved when the information extracted from the imagery about
the target is applied in order to better understand it. Ir reveals
some new information or assist in solving a particular problem.

7. Types of Remote Sensing
There are 2 types of remote sensing:
• Passive Sensors
• Active Sensors
• Active Remote Sensing: Active RS directs its signal to the object
and then checks the response. This type of sensors illuminates its
target. Active sensors measure the reflected light.
For eg: Radarsat-2 is an active sensor.
• Passive Remote Sensing: Passive RS measures reflected light
emitted from the sun. When the sunlight reflects off Earth’s
surface passive sensors capture that light.
For eg: Landsat and Sentinel are passive sensors.

8. Active Remote sensing Instrument
• Radar: It is a sensor assisting in ranging with radio signals. Its
specific feature is the antenna emiting impulses. Based on energy
amount and travelling time, its possible to estimate how far the
target is.
• Lidar: It determines distance with light. Lidar active remote
sensing implies transmitting light impulses and checking the
quantity retrieved. The target location and distance are measured
by multiplying the time by the speed of light.

9. The Electromagnetic Spectrum
The electromagnetic spectrum ranges from short wavelength (like
X-rays) to long wavelength (like radio waves). Human eyes can
possibly see the visible ranges of light(red, green, blue). But sensors
can see beyond human visible ranges. Hence RS is so powerful.
Human eyes can see spectrum ranges 390-700nm. Sensors were
design to capture beyond this wavelengths in the atmospheric
window.
For eg: Near infrared(NIR) is in the 700-1400nm ranges. Vegetation
reflects more green light because that’s how human eyes see it. But
its even more sensitive to near infrared. That’s why indexes like
NDVI is used to classify vegetation.

10. Passive Remote Sensing Instruments
• Spectometer: It distinguishes and analyzes spectral bands.
• Radiometers: Determines the power of radiation emitted by the
objects in particular band ranges(visible, IR, microwave)

12. Spectral Bands
Spectral bands are groups of wavelengths. For eg: Ultraviolet,
visible, near-infrared, thermal infrared and microwave are spectral
bands.
Spectral regions are categorized based on its frequency(v) or
wavelength. There are two types of imagery for passive sensors:
• Multispectral imagery
• Hyperspectral imagery

13. Multispectral Imagery
Multispectral imagery generally refers to 3-10 bands. For eg,
Landsat-8 produces 11 separate images for each scene.

14. Hyperspectral Imagery
Hyperspectral imagery has much narrow bands(10-20nm). A
hyperspectral images has hundreds of thousands of bands.
For eg, Hyperion( part of EO-1 satellite) produces 220 spectral
bands(0.4-2.5um)

15. Geographic Information System:
GIS is a combination of hardware and software that enables the
collection of data from different sources(remote sensing being one
of them). It relates spatial/tabular data, performs spatial/tabular
analysis and designs the layout of a map. In other words, GIS is a
computer assisted system that can input, store, retrieve, analyse
and display geographically referenced information useful for
decision making. The definition of GIS is not that important, but it
must encompass
• Data and concepts concerned with spatial distribution
(Geographical)
• Notion of conveying data, ideas or analysis(Information)
• The sequence of inputs, process and outputs(System)

16. Application of Remote sensing
• Agriculture: Agriculture plays a dominant role in the economics of both
developed and underdeveloped countries. Mapping tool such as satellite and
airborne images are used to classify crops, examine their health, examine
their viability and monitoring farming practices. Remote sensing application
in agriculture includes crop type classification, crop condition assessment,
crop yields estimation, mapping of soil characteristics, mapping of soil
management practices, and compliance monitoring.
• Forestry: Forest are a source of valuable resources for providing food,
shelter, wild life habitant, fuel and many daily supplies like medicinal
plants. Application of remote sensing in forestry include :
• Reconnaissance mapping: It helps in monitoring depletion and measuring
bio physical properties of forest stands.

17. • Commercial forestry : Remote sensing in commercial forestry helps in
collecting harvest information, updating inventory information for timber
supply, broad forest type, vegetation density, bio mass measurement
• Environmental monitoring: Conservation authorities are concerned with
monitoring the quantity, health and diversity of earths forest
• Geology: Geological application of remote sensing include the following :bad
rock mapping, lithogical mapping, structural mapping, sand and gravel
exploration, mineral exploration, hydrocarbon exploration, environmental
geology, sedimentation monitoring and planetary monitoring
• Fisheries: Remote sensing in fisheries provide spatial data on suspended
sediments, dissolve organic matters, phytoplankton, algalblooms and oil slicks
which are useful in management of fish stocks, monitor the water quality and
natural water pollution such as oil spill or algalbloom which are harmful to
aquatic life
• Remote sensing is very useful in identifying Potential Fishing zones(PFZ). This
data is very useful for fisher man because they came to know likely occurrence
of fish sholals which help them for getting more catch

18. References:
• https://eos.com/blog/types-of-remote-sensing/
• https://www.toppr.com/guides/physics/earth/remote-sensing/
• https://tudip.com/blog-post/what-is-remote-sensing-and-its-
applications/

19. THANK YOU