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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
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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.
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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.
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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)
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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.
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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.
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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.
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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.
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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.
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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
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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
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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
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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
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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