Basics of remote sensing, pk mani

Remote Sensing and its Applications in Soil
Resource Mapping(ACSS-754)(2+1)
Dr. P. K. Mani

Bidhan Chandra Krishi Viswavidyalaya
E-mail: pabitramani@gmail.com
Website: www.bckv.edu.in

Outline
1. Definition
2. History of remote sensing
3. Principles of radiation
4. Radiation-target interaction
5. Spectral signatures
6. Resolution
7. Satellite orbits
8. Applications

Remote Sensing Systems:
the Human Eye

• Spectral Resolution: 0.4-0.7 µm
• Spatial Resolution: ~ 1-3 cm @ 20 m
• Radiometric Resolution: ~16-32 shades
B/W or ~100 colors

Remote Sensing: A Definition
"Remote sensing is the science (and to
some extent, art) of acquiring information
about the Earth's surface without actually
being in contact with it.”
This is done by sensing and recording
reflected or emitted energy and processing,
analyzing, and applying that information.

History of Remote Sensing
1609 - Invention of the telescope

Galileo

1859 - First aerial photographer
Gaspard Felix Tournachon, also known as Nadar

1862 - US Army balloon corp


1909 - Dresden International
Photographic Exhibition
1903 - The Bavarian
Pigeon Corps


First flight, Wright Bros., Dec. 1903

1914-1918 - World War I

1908 - First photos from
an airplane

History of remote sensing
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1783: The Marquis d’Arlandes and Pilatre made a voyage near Paris using a
balloon.
Photography using balloon, pigeon
1860: Aerial photos in Russia and the USA
1914-19: The first World War and the second World War (1939-45) had seen
tremendous development in photography
1927: Robert Goddard launched the first liquid-fueled rocket.
1955: Work began on the Baikonur launch site in central Asia.
1957: Sputnik 1 launched from Baikonur (first satellite)
1961: Yuri Gagarin launched in the Vostok 1 capsule, becoming the first
human in space.
1969: Neil Armstrong and Buzz Aldrin became the first humans to walk on the
Moon.
1971: The first Space Station in history, the Russian Salyut 1
1972: (US Landsat1) the concept of imaging from satellites is introduced
1986: France launched the first stereo-image satellite (SPOT1)
1992: The space year (the maturity of remote sensing - 20 years of operation)
1995 The Shuttle-Mir Program (1st phase of the International Space Station
(ISS).
2000 The first 3 astronauts (2 Russian and one American) start to live in the

Types of remote sensing
• Passive: source of
energy is either the Sun
or Earth/atmosphere

• Active: source of
energy is part of the
remote sensor system

– Sun
- wavelengths: 0.4-5 µm
– Earth or its atmosphere
- wavelengths: 3 µm -30
cm

– Radar
- wavelengths: mm-m
– Lidar
- wavelengths: UV,
Visible, and near
infrared

Camera takes photo as example, no flash and flash

Active

Active sensors provide their own
energy source for illumination.

Emit radiation
Radiation reflected is
detected and
measured
LIDAR, RADAR, and
SONAR

Passive

Remote sensing systems which measure
energy that is naturally available are
called passive sensors

Sun’s energy which is
reflected (visible) or
Absorbed and reemitted as thermal
infrared wavelengths
Landsat,
AVHRR

Seven Elements of Remote Sensing
A.
Energy
Source or
Illumination

For photography, the source is light from the sun. Other types
of remote sensing, such as radar, supply their own energy source


B.
Radiation &
Atmosphere

Remote sensing is affected by how well the illuminating energy
penetrates the atmosphere. This is especially important when the
distance involved is great, such as from a satellite


C.
Interaction
with Target

What the remote sensor is really measuring is how the
energy interacts with the target.


D.
Recording of
Energy by the
Sensor

The sensor records the reflected energy it receives

E.
Transmission,
Reception,
and
Processing

All remote sensing systems have some method of transmitting,
receiving, and processing the data. Some satellites actually drop film
canisters to Earth using parachutes. Most remote sensing is now
done digitally, and the data is transmitted using radio waves.

F.
Interpretation
and
Analysis

Computers can do some analysis, but the final
interpretation is up to the human element.

G.
Application

Remotely sensed data isn’t much use unless it is
gathered for a purpose or application.

A. Energy Source or Illumination

Microwave region from about 1 mm to 1 m.

EMR
• Modern physics acknowledges dual nature of
EMR
• The wave-particle duality refers to how EMR
of differing wavelengths behaves, not what it
is
• Low frequency EMR tends to act more like a
wave; higher frequency EMR tends to act
more like a particle

The Nature of Light

• In the 1860s, the Scottish mathematician and physicist James
Clerk Maxwell succeeded in describing all the basic properties of
electricity and magnetism in four equations
• This mathematical achievement demonstrated that electric and
magnetic forces are really two aspects of the same phenomenon,
which we now call electromagnetism

Wave Model
•EMR travels as a set of sinusoidal orthogonal harmonic
waves travelling at the speed of light, (c = 3.0x108ms-1)
Wavelength and frequency are related to the speed
of light as follows:
c = λv; λ = c/v; v = c/λ

Low frequency EMR tends
to act more like a wave;
higher frequency EMR tends
to act more like a particle

Particle Model
• EMR is comprised of tiny particles (quanta) called
photons travelling in a wave-like pattern at the speed of
light
• Intensity is proportional to number of photons
• Total amount of energy is related to wavelength and
frequency by Planck’s constant (h):
Q = hv
Q = hc/λ
where : Q = energy of a quantum

The Foundation of RS
• Differences in how features interact with and
emit EMR allow us to distinguish between
objects based on their unique spectral
characteristics or signatures
• Variations are wavelength dependant; some
things may “look” the same at certain
wavelengths but different in others

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Reading and browsing

Web
http://rst.gsfc.nasa.gov/
http://earth.esa.int/applications/data_util/SARDOCS/spaceborne/
Radar_Courses/
http://www.crisp.nus.edu.sg/~research/tutorial/image.htm
http://www.ccrs.nrcan.gc.ca/resource/tutor/fundam/index_e.php
http://octopus.gma.org/surfing/satellites/index.html

Glossary of alphabet soup acronyms!
http://www.ccrs.nrcan.gc.ca/glossary/index_e.php
• Other resources
• NASA www.nasa.gov
• NASAs Visible Earth (source of data): http://visibleearth.nasa.gov/
• European Space Agency earth.esa.int
• NOAA www.noaa.gov
• Remote sensing and Photogrammetry Society UK www.rspsoc.org
• IKONOS: http://www.spaceimaging.com/
• QuickBird: http://www.digitalglobe.com/
Lillesand, T. M., Kiefer, R. W. and Chipman, J. W. (2004, 5th ed.) Remote
Sensing and Image Interpretation, John Wiley, New York.

Remote sensing web sites
• http:// www.esrin.esa.it - Eurpopean Space Agency
• http://geo.arc.nasa.gov - NASA program
• http://www.spot.com
• French satellite SPOT
• http://www.nasda.go.jp/ - Japan space agency
• http://www.rka.ru./ Russian Space Agency (RSA)
• http://www.coresw.com - Russian imagery source
• http://www.space.gc.ca/ Canadian Space Agency (CSA)
• http://www.ccrs.nrcan.gc.ca/ccrs/ -Canada Center for Remote
Sensing
• http://www.inpe.br/ National Institute for Space Research (Brazil)
• http://www.asprs.org
- American Society
• http://www.man.ac.uk
- Manshester Univ.
• http://www.idrisi.clarku.edu - Idrisi site

All alone in our neighborhood of space

Apollo 12’s Classic Earth Rise from Moon

Ikonos 1 m panchromatic imagery
2000

MODIS Land Reflectance and
Sea Surface Temperature

Remote sensing literature -Books
• Askne, J. (1995). Sensors and Environmental
applications of remote sensing, Balkema, Rotterdam, NL
• Campbell, J. B. , 1996. Introduction to Remote Sensing.
2nd ed.,Taylor and Francis, London
• Dengre, J. (1994). Thematic Mapping from satellite
imagery: Guide book, Elsevier ltd, Boulevard
• Lillesand, T. M. and R. W. Kiefer, 2000. Remote Sensing
and Image Interpretation. 4th ed., John Wiley and Sons, Inc.
New York
• Simonette, D. S. (ed) (1983) Manual of remote sensing,
the Sheridan Press, Falls church

Basics of remote sensing, pk mani

Basics of remote sensing, pk mani

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