Fundamentals of Remote Sensing.ppt of Remote Sensing.pdfFundamentals of Remote SensingFundamentals of Remote Sensing Pranjit Kr Sarma Ph DPranjit Kr. Sarma, Ph.D. Assistant Professor

Fundamentals of Remote SensingFundamentals of Remote SensingFundamentals of Remote SensingFundamentals of Remote Sensing

Pranjit Kr Sarma Ph DPranjit Kr Sarma Ph DPranjit Kr. Sarma, Ph.D.Pranjit Kr. Sarma, Ph.D.Assistant ProfessorAssistant Professor

Department of GeographyDepartment of GeographyMangaldaiMangaldai CollegeCollege

Email: Email: [email protected]

Ph. No +91 94357 04398Ph. No +91 94357 04398

Remote SensingRemote Sensing

►►Remote sensing is defined as theRemote sensing is defined as the►►Remote sensing is defined as the Remote sensing is defined as the acquisition and recording of acquisition and recording of information about an object withoutinformation about an object withoutinformation about an object without information about an object without being in direct contact with that being in direct contact with that objectobjectobjectobject

►►In the general sense of the term, In the general sense of the term, Remote sensing is referred in relationRemote sensing is referred in relationRemote sensing is referred in relation Remote sensing is referred in relation to EMR sensors which are operated to EMR sensors which are operated from space borne platformsfrom space borne platformsfrom space borne platformsfrom space borne platforms

Why Remote Sensing?Why Remote Sensing?Why Remote Sensing?Why Remote Sensing?►►To recognize macroTo recognize macro--patterns which may not patterns which may not

be visible from ground be visible from ground ►►To gain an OVERVIEW of an area To gain an OVERVIEW of an area gg►►To gather information on large areas in To gather information on large areas in

short timeshort timeshort time short time ►►To gather information costTo gather information cost--effectively effectively ►►To gather information on inaccessible placesTo gather information on inaccessible places►►To gather information on inaccessible placesTo gather information on inaccessible places►►To replace conventional sources of To replace conventional sources of

information (topo sheets, census data etc.)information (topo sheets, census data etc.)

A li i f S lli T h lApplication of Satellite Technology

• weather forecasting and monitoring

• communication

• navigation

• military

• earth resource observation

Important Missions

• LANDSAT • SEASAT

• SPOT

• IRS

• TIROS

• HCMM

• NOAA • RADARSAT

Remote Sensing SystemsRemote Sensing Systems

Referencedata

DATA ACQUISITION DATA ANALYSIS

VisualPictorial Visual

QuantitativeUsers

Numerical

Sensor systems Data products Interpretationprocedures

Informationproducts

Sources ofenergy

Propagation

Re-transmissionthrough atmosphere

p gthrough

atmosphere

Reflection on surface features

Types of Remote SensingTypes of Remote SensingTypes of Remote SensingTypes of Remote Sensing

►►Passive Remote SensingPassive Remote Sensing►►Passive Remote SensingPassive Remote Sensing

►►Active Remote SensingActive Remote Sensinggg

• Makes use of sensors that detect the reflected or emitted electro-t e e ected o e tted e ect omagnetic radiation from natural sources most notably the sunsources, most notably the sun.

makes use of sensors that detect reflected responses from objects that are irradiated from that are irradiated from artificially-generated energy

h dsources, such as radar.

The Major Components of Remote-sensing Technology

1. ENERGY SOURCE (PASSIVE SYSTEM: sun, irradiance from earth’smaterials; ACTIVE SYSTEM: irradiance from artificially-generated; y genergy sources such as radar)

2. PLATFORMS (Vehicle to carry the sensor) (truck, aircraft, spaceshuttle satellite etc )shuttle, satellite, etc.)

3. SENSORS (Device to detect electro-magnetic radiation) (camera,scanner, etc)

4. DETECTORS (To convert electro-magnetic radiation into recordedsignals) (film, silicon detectors, etc)

5. PROCESSING (Handling signal data) ( photographic, digital, etc)

6. INSTITUTIONALISATION (Organization for execution at all stages ofremote-sensing technology: international and national organizations,centers, universities, etc

Types of SatellitesTypes of SatellitesTypes of SatellitesTypes of Satellites

Geostationary SatellitesGeostationary Satellites

Sun- synchronous Satellites

Geostationary SatellitesGeostationary Satellites• altitude (36,000 km)

• makes one revolution in 24 hours

• synchronous with the earth’s rotation

• communication and meteorological applications

Sun-synchronous Satellites• Orbital plane is near polar

• altitude such that the satellite passes overall places on earth having the same latitude twice in each orbit at the same local sun timeat the same local sun time

Diagram showing orbit of Sun Synchronous satellite

Diagram Showing adjacent tracks (passes)

What is an image?What is an image?gg►► Data that are organized in a grid of columns and rowsData that are organized in a grid of columns and rows►► Usually represents a geographical areaUsually represents a geographical area

X-axis

How are images made?How are images made?How are images made?How are images made?►►Some simple theoretical concepts need Some simple theoretical concepts need

t b d t dt b d t dto be understoodto be understood►►Light from the sun reflects off the Light from the sun reflects off the

earth’s surfaceearth’s surface

The process of remote sensingThe process of remote sensingThe process of remote sensingThe process of remote sensing

S

SOLAR ENERGY

The process of remote sensingThe process of remote sensingThe process of remote sensingThe process of remote sensing

C

121265652828

E

C33337676

A

A

D

B

Measuring LightMeasuring Light

►►Light can be classified according to the Light can be classified according to the length of the wavelength of the wave Wavelength

G R Ul i l I f d MiX R TV/R di

T�� E�������������� S������� �EMS�

Gamma Rays Ultraviolet Infrared MicrowaveX-Ray TV/Radio

VisibleVisible

˜ 0 4 ˜ 0 7 0.4micrometers

0.7

Measuring Light: BandsMeasuring Light: BandsMeasuring Light: BandsMeasuring Light: Bands►►Human eyes only ‘measure’ visible lightHuman eyes only ‘measure’ visible light►►Sensors can measure other portions ofSensors can measure other portions of►►Sensors can measure other portions of Sensors can measure other portions of

EMSEMS

B����

Spectral SignaturesSpectral Signatures►►Signal received by sensor depends on land Signal received by sensor depends on land

covercover50

e S t l Si t50

% R

efle

ctan

c Spectral Signature unique to healthy vegetation

50

0 %

0

.4 .6 .8 1.0 1.2 1.4

0

Bare EarthWater

Green - Highest reflectance hence we see green treessee green trees

Spectral reflectance of vegetation

lect

ance

per

cent

ref

l

IRB G RNatural colour compositeassignment

of three

wave length

IRB G RInfrared colour composite (FCC)

of threeprimarycolours

B G R

IRS LISS III Image (FCC)

Mathanguri I.B.

Manas National Park

Bansbari Range Office

Satellite Imagery of Manas National Park

B

C M

CBG

G RY

WY MR

BL

B = Blue C = Cyan

Additive color composite Subtractive color composite

G = Green M = MagentaR = Red Y = YellowW = White BL = Black

METHODS OF COLOUR COMPOSITEMETHODS OF COLOUR COMPOSITE

Dense Forest River Water Body

Open Forest Settlement

AgricultureAgricultureFallow Land

Typical Tone and Texture of Common Features GIS UNIT,

Two types of imagesTwo types of imagesTwo types of imagesTwo types of images►► REMOTELY SENSED imagesREMOTELY SENSED images Continuous dataContinuous data

• Measured Values (light)• Quantitative

• THEMATIC Images Discrete data

• Values only indicate class• Qualitative

Continuous dataContinuous data• Two types:

Panchromatic ( 1 Band/layer)• Panchromatic ( 1 Band/layer)

• Multispectral ( 2 or more Bands)

Viewing continuous imagesViewing continuous imagesg gg g•• Each band or layer is viewable as a separate Each band or layer is viewable as a separate

imageimageT������� M����� B��� 1

B��� 4

B��� 5

Band CombinationsBand Combinations►►Features can become more obviousFeatures can become more obvious

2,3,1 (RGB)4,3,2 (RGB)2,3,4 (RGB)

Urban

Vegetation

Exe…

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