Submitted by-ANKIT SINGH

ANMOL CHOUDHARYB.TECH(civil engg.)

2010-2014 batch

REMOTE SENSING Remote Sensing is the

science of acquiring information about the earth’s surface without actually being is physical contact with surface.

•This is done by sensing and recording reflected or emitted energy and processing , analyzing and applying that information.

•The characteristics of an object can be determined using reflected or emitted electromagnetic radiation from the object i.e. each object has unique and different characteristics of reflection or emission depending upon different environmental condition.

•The data collected by remote sensing is called remotely sensed data.

•The remote sensing datas are used in agriculture , land use , forestry , geology , hydrology , oceangraphy and environment operated by computer or manually.

PRINCIPLE OF REMOTE SENSING All objects on the surface of earth have spectral

signature. A spectral signature of an object or ground surface is a set of values for the reflectance or radiance of the feature with well defined wavelength interval.

The response of ground surface material to incident radiation is the reflectance and the energy emitted by all objects as a function of their temperature and structure is the emittance. The reflectance and emittance determine the signature.

Classification of remote sensingActive remote sensing

generates and uses its own source of energy (EM) , which is directed towards the objects and return energy is measured.

•Passive remote sensingit uses sun as a source of

electromagnetic energy and records the energy that is naturally radiated or reflected from the objects.

Componenet of remote sensing A source of electromagnetic energy ( from sun , self

emission).

Transmission of the energy from the source of to the surface of earth ( scattering & absorption).

Interaction of electromagnetic radiation with the earth surface , reflection and re-emission.

Transmission of energy from the surface to remote sensor.

Sensor data output.

Processing and analyzing the sensor data output.

Energy source

targetSensor

Electromagnetic radiation

Transmission of emitted or reflected EmRadiation from the target

Component of a remote sensing system

Idealized remote sensing systemElectromagnetic energy of all

wavelengths and of uniform intensity is produced by an ideal source (SUN).

In this system enegy propagates from the source without loss to a homogenous target and the enegy of various wavelenghts interacts and emitted enegy.

Components of an ideal remote sensingElectromagnetic enegy source. (SUN)

Energy propagation

Energy interaction

Return signal

Recording

Supply of information in the desired form

Remote sensing platformThe base at which sensor is mounted is called remote sensing platform.

Types of remote sensing sensor

1) Air borne platform

sensor mounted on a aircraft and information recorded regarding the earth surface by capturing.

2) Spaced based platform

sensor mounted on a satelight and have more advantage than air borne platform and provides synoptic view ( observations of large area in a single image).

3) ground platform

a ladder , a scaffold or a truck having a sensor but not used in now days.

Remote sensing satelightsGeostationary satellites

positioned in equatorial plane at altitude of 36000 km and the orbit in which it moves is called geostationary orbit. These satellites have the same period as the earth and become stationary.

•Sun-synchronous satelliteThese are RS Satellites which resolve

around earth in a sun-synchronous orbit.(altitude 700-1500km) defined by its fixed inclination angle from the earth’s N-S axis. Such satellites provides the observation of scenes of the same area under condition of uniform illumination.

DATA PRODUCTS USED IN REMOTE SENSING PHOTOGRAPHS

it may be aerial . The photograph taken with an aerial camera having the camera station in the air and the axis of the camera vertical or nearly vertical . It may be of different type-

vertical photograph

the axis of camera is vertical or nearly vertical.

oblique photograph

axis of camera intastionally tilted from the

vertical.

Low oblique photographwhen angle of inclination at 30 degree with the

vertical.High oblique photograph

when angle of inclination at 60 degree with the vertical.Convergent photographlow oblique photograph taken with two ameraexposed at successive exposure station with the their axis tilted at a fixd inclination from the vertical in direction of flight.

Trimetrogen photographcombination of vertical and low oblique photograph exposed simultaneously from the air station with two camera.

Mosaics The photomaps obtained by assembling two or more photograph to form a single picture of an area. photograph prepared photomap.

Orthophotothe pictorial depiction of the terrain derived from aerial photography in such a way that there are no relief or tilt displacement is called orthophoto.

Satellites imagery or digital imageIn satellite remote sensing the data of an area of earth’s surface is collected in digital form using sensor & scanners and stored on computer compatiable tapes (CCT). Or some other storage device. This data in the digital form is termed as imagery.Some indian remote sensing satellites (IRS)satellite for earth observation (SEO) called bhaskara-1 launched in june 1979 by soriet launch vehicle.

SEO-2 (bhaskara -2) launched in nov 1981 by soriet cosmodrome.

india’s first semi-operational remote sensing satellites(IRS) launched in sep 1987 by soriet union.

IRS series of satellites launched by IRS mission are-IRS1A,IRS1B,IRS1C,IRS1D & IRSP4.

Application of remote sensingContinuous monitoring of the earth’s

natural and other resources.

Determine impact of man’s activities on air , water and land.

Remote sensor data provides neccessaryinformation for making sound decision and in formulating policy regarding land use and resources development.

Detects forest fire before the smoke appears.

It detects the plant disceases before spotled.

It detects the presence of pollution on earth’s feature.

It is much suitable for GIS.

ATMOSPHERIC WINDOW

the selection of portion spectrum which has high transmission of EMR is called atmospheric window . In other words the wavelenghts which are able to pass through the atmosphere without loss or a minimum loss are called atmospheric window.