RSGIS KEY PART A F (1).pdf

S.BHARATHIMOHAN & B.RAJESHKANNA Page 1 of 16 REF: PRIST UNIVERSITY

This work is delivering new means of mapping prehistoric and historic sites in three

dimensions rather than traditional two-dimensional methods.

M.TECH (ENV. ENGG), SEM II : REMOTE SENSING AND GEOGRAPHICAL INFORMATION SYSTEM

UNIT - I (Part A)

1. DEFINE REMOTE SENSING?

Remote Sensing is the science and art of obtaining information about an object by a recording

device (sensor) that is not in physical contact with the object by measuring portion of reflected or

emitted electromagnetic radiation from the earths surface.

2. GIVE TWO REMOTE SENSING APPLICATIONS OF NATURAL HAZARDS.

Areas vulnerable to earthquakes, floods, cyclones, storms, drought, fire, volcanoes, landslides, soil

erosion can be used to accurately predict future disasters.

3. GIVE TWO REMOTE SENSING APPLICATIONS OF ARCHAEOLOGY.

Remote sensing in archaeology: past, present and future perspectives

To the preservation and exploitation of cultural heritage, particularly archaeological assets,

has recently directed Remote Sensing applications above all towards the multi-temporal

monitoring of existing archaeological sites and their surrounding areas, to study the

evolution over time of the most significant environmental and anthropic parameters (change

in the use of soil, characteristics of vegetation, urban sprawl, thermal anomalies, etc.).

4. MENTION RECENT TWO GEOSTATIONARY SATELLITES SENT TO SPACE IN ISRO PROGRAM.

GSAT - 16 on 07.12.2014

GSAT - 14 on 05.01.2014

5. MENTION RECENT TWO SUN-SYNCHRONUS SATELLITES SENT TO SPACE IN ISRO PROGRAM.

SARAL on 25.02.2013

RISAT 1 on 26.4.2012

6. WHAT ARE THE BASIC PROCESSES AND ELEMENTS INVOLVED IN ELECTROMAGNETIC REMOTE

SENSING OF EARTH RESOURCES?

Two main processes involved in passive or electromagnetic remote sensing are

(i) Data Acquisition (ii) Data Analysis

(i) Data Acquisition: It comprises the following distinctive elements namely

a. Energy sources


b. Propagation of energy through the atmosphere

c. Energy interactions with the earth surface features

d. Air borne, space borne sensors to record the reflected energy

e. Generation of sensor data as pictorial or digital information

(i) Data Analysis: It can be broadly classified as

a. Visual Image Interpretation: This involves the examination of data with various viewing

instrument to analyze pictorial data.

b. Digital Image Processing

Sensing

: When computers are used to analyze digital data then the process is

called digital image processing.

7. WRITE ABOUT ATMOSPHERIC WINDOWS.

These are certain regions of the electromagnetic spectrum which can penetrate through the

atmosphere without any significant loss of radiation. Such regions are called as atmospheric

windows. In these regions the atmospheric absorption is low (i.e.) the atmosphere is particularly

transmission of energy.

Atmospheric Windows (Wavelength)

Visible 0.38 - .72 m

Near and middle infrared 0.72 3 m

Thermal infrared sensing 8 14 m

Radar sensing 1mm 1m

8. BRIEFLY WRITE ABOUT SPECTRUM.

The electromagnetic spectrum (EMS) may be defined as the ordering of the radiation according to

wavelength, frequency or energy. The electromagnetic spectrum (EMS) can be explained as the

continuum of energy that ranges from meters to nanometers in wavelength.

9. BRIEFLY WRITE ABOUT THE ENERGY INTERACTION WITH ATMOSPHERE.

All the electromagnetic radiation before and after it has interacted with the earths surface, has to

pass through the atmosphere before it is detected by the Remote Sensors irrespective of its source.

This distance is called Path Length of Atmosphere. This path length varies depending upon the

types of sensors.

In the case of space borne sensors, the sunlight passes through the full thickness of the earths

atmosphere two times on its journey from source to sensor (two path lengths). In air borne sensors,

the sensors detect energy emitted directly from objects on the earth such that only single

atmospheric path length is involved.


The net effect of the atmosphere depends upon the differences in path length, the magnitude of

energy signal being sensed, the atmospheric conditions and the wavelengths. These effects are due

to the mechanisms of Atmospheric scattering and Absorption (Atmospheric Effects).

10. DEFINE ACTIVE SYSTEMS OF REMOTE SENSING.

Description Active Systems of RS

Energy Source Own energy

Region of spectrum in which they operate Microwave region of the electromagnetic spectrum

Wavelength Longer than one mm

Example SAR (Synthetic Aperture Radar)

11. DEFINE PASSIVE SYSTEMS OF REMOTE SENSING

Description Passive Systems of RS

Energy Source Depend on solar radiation

Region of spectrum in which they operate Visible and Infrared region of the electromagnetic

spectrum

Wavelength Range from 0.4 to 10 m

Example Any electromagnetic remote sensing system

(Camera without flash)

12. DIFFERENTIATE BETWEEN SELECTIVE AND NON-SELECTIVE SCATTERING.

Scattering is the unpredictable diffusion of radiation caused by the molecules of the gases, dust and

smoke in the atmosphere. Scattering is based on the particle sizes in the atmosphere.

SELECTIVE SCATTERING:

a. Rayleighs scattering

It happens in the upper part of the atmosphere. This happens when radiation interacts with

atmospheric molecules and other tiny dust particles, which are smaller in diameter that the

wavelength of the interacting radiation wavelength. Ex. The blue sky concept.

b. Mie scattering

This is lower atmosphere scattering from 0 to 5 Km. It happens when the atmospheric particles

diameter are of same size as that of the wavelength of radiations being sensed. Spherical particles

of water vapour, pollen grains and dust are the main causes of Mie scattering.

NON-SELECTIVE SCATTERING:

Non-selective scattering occurs when the size of effective atmospheric particles are much larger

than the wavelength of radiations. Water droplets, ice and snow crystals are the main causes of this

scattering.


13. DIFFERENTIATE BETWEEN GEOSTATIONARY AND SUN-SYNCHRONOUS SATELLITES.

GEOSTATIONARY SATELLITES SUN-SYNCHORONOUS SATELLITES

These satellites stationary with respect

to given position of the earth surface.

These rotate at the same rate as the mean rotation of

earth around the sun and on the plane near to polar.

Weather and Communication Purpose Earth Resources Purpose

Altitude : 35,790 KM Approx. Altitude : 300 - 800 KM Approx.

Ex : GSAT 16 Ex : RISAT 1

14. WRITE ADVANTAGES OF REMOTE SENSING. 1. Remote sensing detects features, which are not visible to the human eye, such as a dense

forest, Antarctic region and in accessible areas. 2. It provides up to date and continuous information about an area, such as the changing

pattern of wealth, land use etc. 3. It helps the planners for formulating policies and programmes to achieve the holistic

functioning of environment, because of its speedy, accurate and up-to-date information. 4. It caters the information needed by the agriculturists to identify the areas affected by pests,

crop disease, water logging, wasteland etc. 5. It spots the areas of natural disasters such as Tsunami, drought prone, flood affected and

cyclone-hit areas. It is highly useful for detecting damage, estimating the loss, for providing relief, rehabilitation and helps in reconstruction.

6. The most important utility of remote sensing is into the science of cartography. It enables the cartographers to prepare thematic maps like geological maps, soil maps, population maps etc with greater accuracy and speed.

15. WRITE RELATION BETWEEN WAVELENGTH AND FREQUENCY.

Wavelength

The distance from one wave peak to another is called wavelength. It is measured in meters or

fraction of meters such as nanometers (nm, 10-9 meters), micrometers (m, 10-6 meters),

centimeters (cm, 10-2 meters). Wavelength is usually represented by Greek letter lambda ().

Frequency

The number of wave peaks passing a fixed point in a given period of time. It is measured in hertz

(Hz). The speed of EM energy is constant and its value is 3X108 m/sec.

Wavelength and Frequency are related by the following formula:

C = () x n

C = Speed of light (3X108 m/sec)

() = Wavelength (m)

n = Frequency (cycles per second, Hz)


16. BRIEFLY DESCRIBE EFFECT OF ATMOSPHERE ON ELECTROMAGNETIC RADIATION

When electromagnetic radiation travels through the atmosphere, it may be absorbed or scattered

by the constituent particles of the atmosphere.

Absorption converts the radiation energy into excitation energy of the molecules.

Scattering redistributes the energy of the incident beam to all directions. The overall effect

is the removal of energy from the incident radiation.

17. BRIEFLY WRITE ABOUT SCATTERING?

Scattering is the unpredictable diffusion of radiation caused by the molecules of the gases, dust and

smoke in the atmosphere. Scattering is based on the particle sizes in the atmosphere.

There are four different types of scattering. They are

a. Rayleighs scattering b. Mie scattering

c. Non-selective scattering d. Ramans scattering

18. DIFFERENTIATE BETWEEN RADIANT FLUX AND IRRADIANCE.

Radiant Flux: The amount of radiant energy per unit time either emitted, received or transmitted

across an area is called radiant flux, units: J s-1 = W(att).

Irradiance: The irradiance is the radiant flux density received by a surface (W m-2).

19. DIFFERENTIATE BETWEEN RADIANT ENERGY AND RADIANT INTENSITY

Radiant energy denoted by the symbols Q the measures of all the energy received at a particular

point or all the energy contained in a particular radiation field. Radiant energy is measured in watt-

seconds

Radiant intensity, denoted by the letter I, is the amount of power radiated per unit solid angle,

measured in W/sr (watt per steradian)

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UNIT - II (Part A) 1. DEFINE RADAR.

RADAR (RAdio Detection And Ranging) is an object detection system, which uses radio waves to

determine the range, altitude, direction or speed of objects. It can be used to detect aircraft, ships,

spacecraft, guided missiles, motor vehicles, weather formations and terrain.

2. DEFINE LIDAR.

LIDAR (Light Detection And Ranging or Laser Imaging Detection And Ranging) is an optical remote

sensing technology that can measure the distance to, or other properties of, targets by illuminating

the target with laser light and analyzing the backscattered light. LIDAR technology has applications

in geometrics, archaeology, geography, geology, geomorphology, seismology, forestry, remote

sensing, atmospheric physics, etc.

3. WRITE RADAR EQUATION USED IN MICROWAVE REMOTE SENSING.

The power Pr returning to the receiving antenna is given by the equation:

where

Pt = transmitter power

Gt = gain of the transmitting antenna

Ar = effective aperture (area) of the receiving antenna

= radar cross section, or scattering coefficient, of the target

F = pattern propagation factor

Rt = distance from the transmitter to the target

Rr = distance from the target to the receiver.

In the common case where the transmitter and the receiver are at the same location, Rt = Rr and

the term Rt Rr can be replaced by R4, where R is the range. This yields:

4. MENTION RADAR PRINCIPLE WITH FLOW CHART.


A radar system has a transmitter that emits radio waves called radar signals in predetermined

directions. When these are exposed to an object, they are usually reflected or scattered in many

directions. Radar signals are reflected especially well by materials of considerable electrical

conductivityespecially by most metals, by seawater and by wet lands. Some of these make the

use of radar altimeters possible. The radar signals that are reflected back towards the transmitter

are the desirable ones that make radar work. If the object is moving either toward or away from the

transmitter, there is a slight equivalent change in the frequency of the radio waves, caused by the

Doppler effect.

5. DEFINE BACK SCATTERING COEFFICIENT.

The backscattering, or backward scattering, coefficient, in units of m-1. It indicates the

attenuation caused by scattering at angles from 90 to 180. bb is commonly estimated from

measurements of the VSF around a single fixed angle.

6. WRITE ANY 4 BANDS USED IN MICROWAVE REM. SEN. AND MENTION THEIR WAVELENGTHS.

Band

Microwave frequency bands

Frequency

range

Wavelength

range Typical uses

L band 1 to 2 GHz 15 cm

to 30 cm Military, GPS, mobile phones (GSM), amateur radio

S band 2 to 4 GHz 7.5 cm

to 15 cm

Weather radar, surface ship radar and some

communications satellites (microwave ovens, microwave

devices/communications, mobile phones, wireless LAN,

Bluetooth, ZigBee, GPS, amateur radio)

C band 4 to 8 GHz 3.75 cm

to 7.5 cm long-distance radio telecommunications

X band 8 to 12 GHz 25 mm

to 37.5 mm

satellite communications, radar, terrestrial broadband,

space communications, amateur radio

7. WRITE ABOUT NADIR IN REMOTE SENSING

The surface directly below the satellite is called the Nadir point. Nadir also refers to the downward-

facing viewing geometry of an orbiting satellite, such as is employed during remote sensing of the

atmosphere, as well as when an astronaut faces the Earth while performing an spacewalk.


8. MENTION MAJOR COMPONENTS OF REMOTE SENSING TECHNOLOGY.

1. Energy Source or Illumination

2. Radiation and the Atmosphere

3. Interaction with the Target

4. Recording of Energy by the Sensor

5. Transmission, Reception and Processing

6. Interpretation and Analysis

7. Application

9. WHAT IS FORWARD LOOKING INFRARED SYSTEM (FLIR) IN REMOTE SENSING?

An airborne, electro-optical thermal imaging device that detects far-infrared energy, converts the

energy into an electronic signal, and provides a visible image for day or night viewing. Also called

FLIR.

10. WHAT IS MEANT BY SIDE LOOKING AIRBORNE RADAR (SLAR)?

SLAR is an aircraft or satellite-mounted imaging radar pointing perpendicular to the direction of

flight (hence side-looking).

11. DEFINE RADIOMETRIC RESOLUTION?

While the arrangement of pixels describes the spatial structure of an image, the radiometric

characteristics describe the actual information content in an image. Every time an image is acquired

on film or by a sensor, its sensitivity to the magnitude of the electromagnetic energy determines

the radiometric resolution. The radiometric resolution of an imaging system describes its ability to

discriminate very slight differences in energy. The finer the radiometric resolution of a sensor, the

more sensitive it is to detecting small differences in reflected or emitted energy.


12. DIFFERENTIATE BETWEEN FAR RANGE AND NEAR RANGE IN RADAR USING REMOTE SENSING.

The near field and far field regions of an isolated source of electromagnetic radiation are generally

used terms in antenna measurements and describe regions around the source where different

parts of the field are more or less important. The boundary between these two regions depends on

the geometric dimensions of the source and the emitted by the source dominant wavelength . In

the region of near field of an antenna the angular field distribution is dependent upon the distance

from the antenna. The different parts of energy emitted by different geometric regions of the

antenna have got a different running time and the resultant field cannot be constructively

interfered to an evenly wave front.

13. SHOW INCIDENCE ANGLE AND DEPRESSION ANGLE USING DIAGRAM.

Angle of incidence

The angle formed by a ray or wave, as of light or sound, striking a surface and a line

perpendicular to the surface at the point of impact.

Depression angle

In aerial photography, the angle between the optical axis of an obliquely mounted air camera and

the horizontal.

14. MENTION THE OPERATING TEMPERATURES OF THREE PHOTON DETECTORS, WHICH ARE

COMMON IN USE.

Type Operating temperature

Mercury-doped germanium Ge:Hg Spectral range: 3 - 14 35 Kelvin

Indium antimonide In Sb Spectral range: 3 - 5 > 77 Kelvin

Mercury Cadmium telluride Hg cd Te Spectral range: 8 - 14 77 Kelvin

(MCT)

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UNIT - III (Part A) 1. WHAT IS MEANT BY THE VISUAL IMAGE INTERPRETATION?

Image interpretation is defined as the act of examining images to identify objects and judge their

significance. An interpreter studies remotely sensed data and attempts through logical process to

detect, identify, measure and evaluate the significance of environmental and cultural objects,

patterns and spatial relationships. It is an information extraction process.

2. WRITE ANY FOUR ELEMENTS OF VISUAL IMAGE INTERPRETATION PROCESS.

1. Shape 2. Size 3. Tone 4. Texture 5. Pattern 6. Shadow 7. Location 8. Association

3. WHAT ARE THE TWO DIFFERENT TYPES OF KEY USED IN VISUAL IMAGE INTERPRETATION?

a. Selective key b. Elimination key

4. WHAT ARE THE TWO IMAGE PRE-PROCESSING TASKS NEED TO BE PERFORMED BEFORE

PROCESSING AN IMAGE?

Before an interpreter undertakes the task of performing visual interpretation, two important issues

should be addressed.

The first is the definition of classification system or criteria to be used to separate the

various categories of features occurring in the images.

The second important issue is the selection of minimum mapping unit (MMU) to be applied

on the image interpretation. MMU refers to the smallest size areal entity to be mapped as a

discrete area.

5. WHY THERE IS NEED OF IMAGE ENHANCEMENT?

Low sensitivity of the detectors, weak signal of the objects present on the earth surface, similar

reflectance of different objects and environmental conditions at the time of recording are the

major causes of low contrast of the image. The main aim of digital enhancement is to amplify these

slight differences for better clarity of the image scene. This means digital enhancement increases

the separability (contrast) between the interested classes or features.

6. WHAT IS THE DIFFERENCE BETWEEN SUPERVISED AND UNSUPERVISED CLASSIFICATION OF

IMAGE?

1. Supervised classification - The analyst identifies in the imagery homogeneous representative

samples of the different surface cover types (information classes) of interest. These samples are

referred to as training areas.


2. Unsupervised classification It is in essence reverses the supervised classification process.

Spectral classes are grouped first, based solely on the numerical information in the data, and are

then matched by the analyst to information classes (if possible).

7. WITH ONE EXAMPLE PLEASE EXPLAIN THE NEED OF IMAGE TRANSFORMATION?

All the transformations in image processing of remotely sensed data allow the generation of a new

image based on the arithmetic operations, mathematical statistics and fourier transformations. The

new image or a composite image is derived by means of two or more band combinations,

arithmetics of various band data individually and/ or application of mathematics of multiple band

data. The resulting image may well have properties that make it more suited to a particular purpose

than the original.

Example:

Near infrared and red bands of an image set are widely used as a vegetation index, as an attribute

of vegetative cover, with a particular biomass and green leaf area index of the area covered by the

image.

8. DEFINE SELECTIVE KEY USED IN VISUAL IMAGE PROCESSING.

Selective keys are arranged in such a way that an interpreter simply selects the example that closely

corresponds to the object the interpreter is trying to identify.

Ex. Industries, landforms, etc.

9. DEFINE ELIMINATIVE KEY USED IN VISUAL IMAGE PROCESSING.

Elimination keys are arranged such that the interpreter follows a precise stepwise process that

leads to the elimination of all items/targets, except the one that the interpreter is trying to identify.

Ex. Agricultural studies and Forestry applications.

10. DIFFERENTIATE BETWEEN GEOMETRIC CORRECTION AND RADIOMETRIC CORRECTION.

Geometric Correction Methods

Frequently information extracted from remotely sensed images is integrated with map data in a

geographical information system. The transformation of a remotely sensed image into a map with a

scale and projection properties is called geometric correction.

Radiometric Correction Methods

The primary function of remote sensing data quality evaluation is to monitor the performance of

the sensors. The performance of the sensors is continuously monitored by applying radiometric

correction models on digital Image data sets.


11. WHAT IS BIAS IN DIGITAL IMAGE PROCESSING?

If the sky is clear with no scattering, then the radiance reflected from the earth surface feature in

any of the region of the electromagnetic spectrum should be the same. This is the ideal case. In

reality, because of the presence of haze, fog, or atmospheric scattering, there always exists some

kind of unwanted signal value called bias.

The bias is the amount of offset for each spectral band.

12. WHAT IS RANDOM NOISE IN DIGITAL DATA OF REMOTE SENSING?

Image noise is any unwanted disturbance in image data that is due to limitations in the sensing and

data recording process. The random noise problems in digital data are characterized by

nonsystematic variations in gray levels from pixel to pixel called bit errors.

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UNIT - IV (Part A) 1. DEFINE GIS?

GIS can be defined as a system which involves collecting/capturing, storing, processing,

manipulating, analyzing, managing, retrieving and displaying data which is, essentially, referenced

to the earth.

2. WHAT ARE THE VARIOUS SOURCES FROM WHICH DATA CAN BE DERIVED TO BE USED FOR GIS?

The data are usually derived from a combination of hard copy maps, aerial photographs, remotely

sensed images, reports, survey documents, etc.

3. MENTION THREE KINDS OF DATA REQUIRED IN GIS?

a. Raster Data : Remotely Sensed Imagery, Aerial Photographs, Scanned images, etc

b. Vector Data : Point, Line and Polygon

c. Attribute Data : Also called non spatial data or a spatial data or tabular data

5. WRITE TYPES OF BUFFERING IN GIS.

Point Feature Buffering : Round

Line and Polygon Feature Buffering : Round and Flat

6. WRITE ABOUT NEIGHBORHOOD FUNCTIONS IN GIS.

Neighborhood Function analyzes the relationship between an object and similar surrounding

objects. For example, in a certain area, analysis of a kind of land use is next to what kinds of land

use can be done by using this function. This type of analysis is often used in image processing. A


new map is created by computing the value assigned to a location as a function of the independent

values surrounding that location. Neighborhood functions are particularly valuable in evaluating the

character of a local area.

7. WRITE ABOUT MAP OVERLAY IN GIS.

The combination of several spatial datasets (points, lines or polygons) creates a new output vector

dataset, visually similar to stacking several maps of the same region.

8. WRITE ABOUT FEATURE IDENTIFIER IN GIS.

Point Data: these are single geometric positions. Spatial locations of points are given by their

coordinates (x, y). Features such as wells, buildings, survey control points, monuments and

mines etc

Line and String Data: These are obtained by connecting points. Line connects two points and a

string connects two or more lines. These are formed by features such as highways, railways,

canals, rivers, pipelines, power lines etc.

9. WHAT ARE FILTERS IN GIS?

The Filter is a tool which can be used to either eliminate spurious data or enhance features

otherwise not visibly apparent in the data. Filters essentially create output values by a moving,

overlapping 3x3 cell neighborhood window that scans through the input raster.

There are two types of filters available in the tool: low pass and high pass.

10. WHAT IS RECLASSIFICATION PROCESS IN GIS?

Reclassification operations merely repackage existing information on a single map.

11. DIFFERENTIATE RASTER AND VECTOR DATA? SL.NO. VECTOR DATA RASTER DATA

1 Represented by point, line and polygon Point, line & polygon everything in the form

of Pixels

2 Relatively small file size (small data volume) Large file size

3 Excellent representation of networks Networks are not so well represented

4 A large no. of attributes can be attached,

hence more information intensive. Only one pixel value represents each grid cell

5 Features are more detailed & accurate Generalization of features (like boundaries)

hence accuracy may decrease

6 Assigning projection and transformations are

less time taking and consumes less memory.

Coordinate-system transformations take

more time and consume a lot of memory


12. WRITE TWO ADVANTAGES OF GIS OVER OTHER METHODS.

(a) Information can be stored, manipulated and retrieved with the help of computer and software

within no time, which is the essence of GIS.

(b) It removes the need of paper plans and associated documents and speeds up the production of

information in the form of maps, tables, etc by rapidly updating and editing the data in computers.

13. DIFFERENTIATE SPATIAL AND NON-SPATIAL DATA.

Spatial Data (graphical data): Consists of natural and cultural features that can be shown with lines

or symbols on maps, or that can be seen as images or photographs.

Non-Spatial Data

regional planning and site investigation,

(Attribute Data): Describes geographic regions or defines characteristics of spatial

features within geographic regions.

These data usually alphanumeric and provide information such as color, texture, quantity and

quality.

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UNIT - V (Part A) 1. MENTION FOUR MAJOR APPLICATIONS OF REMOTE SENSING IN CIVIL ENGINEERING.

In civil engineering projects, RS and GIS techniques can become potential and indispensable tools.

Various civil engineering application areas include

terrain mapping and analysis,

water resources engineering,

town planning and urban infrastructure development,

transportation network analysis,

landslide analysis, etc.

2. WHAT IS IMAGING AND NON-IMAGING SENSORS?

A sensor classified as a combination of passive, non-scanning and non-imaging method is a type of

profile recorder, for example a microwave radiometer.

A sensor classified as passive, non-scanning and imaging method, is a camera, such as an aerial

survey camera or a space camera.

3. DIFFERENTIATE BETWEEN BLACK BODY AND GRAY BODY?

Black body

A blackbody allows all incident radiation to pass into it (no reflected energy) and internally absorbs

all the incident radiation (no energy transmitted through the body). This is true of radiation for all


wavelengths and for all angles of incidence. Hence the blackbody is a perfect absorber for all

incident radiation.

Gray body

A body that emits radiant energy and has the same relative spectral energy distribution as a

blackbody at the same temperature but in smaller amount.

4. WHAT ARE THE COMPONENT SUBSYSTEMS OF GIS?

Data Input Subsystem

Data Storage, Editing and Retrieval Subsystem

Data Manipulation and Analysis Subsystem

Data Output and Display Subsystem

5. WHAT ARE THE FUNCTIONALITIES OF GIS?

Capture

Transfer

Validate and edit

Store and structure

Restructure

Generalize

Transform

Query

Analyze

Present

6. WHAT IS MMU IN RASTER DATA MODEL?

The linear dimension of each cell defines the spatial resolution of data or the precision with which

the data is presented. Thus, the size of an individual pixel or cell is determined by the size of the

smallest object in the geographic space to be represented. The size is also known as Minimum

Mapping Unit (MMU).

7. WHAT IS MEANT BY THE SPATIAL RESOLUTION?

Spatial Resolution : Defined by area or dimension of each cell

Spatial Resolution : (cell height) X (cell width)

High resolution : cell represents small area

Low resolution : cell represents larger area


8. WHAT IS FCC?

FCC = False Colour Composite

FCC refers to a group of color rendering methods used to display images in color which were

recorded in the visible or non-visible parts of the electromagnetic spectrum. A false-color image is

an image that depicts an object in colors that differ from those a photograph (a "true-color" image)

would show.

9. DRAW DIAGRAMS FOR ANY TWO SURFACE SCATTERINGS.

10. DISCRIMINATE BETWEEN BLACK BODY AND WHITE BODY.

A black body is an idealized physical body that absorbs all incident electromagnetic radiation,

regardless of frequency or angle of incidence.

A white body is one with a "rough surface [that] reflects all incident rays completely and uniformly

in all directions.

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1. Energy Source or IlluminationGray body

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RSGIS KEY PART A F (1).pdf