1. Remote sensing involves acquiring information about the Earth's surface from a distance, without direct contact, by recording reflected or emitted energy. 2. Remote sensing utilizes electromagnetic energy from the sun that interacts with objects on Earth's surface. This energy is reflected, absorbed, or emitted and detected by sensors to form images. 3. Remote sensing has various applications in civil engineering like terrain mapping, hydrological studies, urban planning, and infrastructure development by providing geospatial data to assess terrain and land features.

1. Geoinformatics: Remote Sensing
Advanced Engineering Surveying &
Geoinformatics
CIEN-01304

2. Remote sensing is the science 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.
Remote Sensing
Introduction

3. • Most remote sensing system utilizes the suns energy which travel
through the atmosphere are selectively scattered observed depending
upon the composition of the atmosphere and wavelength involved.
• These radiations reaching earth interacts with the objects.
Some of these radiations are absorbed , reflected or emitted back to
the sensors and that recorded and processed in the form of image
which is then analyzed to extract the information about the objects
• Finally information extracted are applied In decision making and
solving particular problem.
Basic Principle of Remote Sensing

4. Solar Energy
Absorption
Scattering
Reflected energy
Incident Radiation
Thermal emission
Transmission
Platforms
& Sensors
Ground Borne
Air Borne
Antenna
Data Processing
Data Products Soft Copy
Data Products Hard Copy
Visual Interpretation
Digital Interpretation
Outputs HardCopy
Outputs Softcopy
Space Borne
Decision Making

6. Various
Platforms
Remote Sensing through
instrument

7. Electromagnetic energy is a term used to describe all the different
kinds of energies released into space by stars such as the sun. these
kinds of energy such as
Electromagnetic Energy
1. radio waves
2. TV waves
3. Radar waves
4. Heat (infrared)
5. Light
6. Ultraviolet
7. X-rays
8. Microwaves
9. gamma waves

8. Longer wavelength –
lower frequency

9. Electromagnetic Spectrum

10. • Human eyes only ‘measure’ visible light
• Sensors can measure other portions of EMS
Bands
Measuring Light: Bands

11. Types of satellite orbits
Geostationary
Polar

12. Types of Satellite Orbits
Geostationary Orbits
These satellite appears stationary with respect to the Earth's surface.
Generally placed above 36,000 km from the earth.

13. Communication Satellites are in GEOSYNCHRONOUS ORBIT
(Geo = Earth + synchronous = moving at the same rate).
This means that the satellite always stays over one spot on Earth.
The area on earth that it can “SEE” is called the satellite’s
“FOOTPRINT”
Types of Satellite Orbits
Geostationary Orbits

14. Types of Satellite Orbits
Polar Orbits
• A Polar Orbit is a particular
type of Low Earth Orbit.
• The satellite travels a North –
South Direction, rather than
more common East-West
Direction

15. Types of Satellite Orbits
Polar Orbits

16. • As the satellite revolves around the Earth, the sensor
"sees" a certain portion of the Earth's surface.
• The width of the strip imaged is referred to as the swath
width.
SWATH

17. • Stage-1: Source of energy
• Stage-2: Transmission of EMR towards the Object
• Stage-3: Interaction of EMR with the Object
• Stage-4: Transmission of Interacted EMR towards
the Sensor
• Stage-5: Recording of the Image by the Detector
• Stage-6: Analysis of the Imagery
Six Stages in Remote Sensing

19. • Passive: source of energy is
either the Sun or
Earth/atmosphere
- Sun
wavelengths: 0.4-5 µm
- Earth or its atmosphere
wavelengths: 3µm -
30cm
• Active: source of energy is
part of the remote sensor
system
- Radar
wavelengths: mm-m
- Lidar
wavelengths: UV, Visible,
and near infrared
Camera takes photo as example, no flash and flash
Types of Remote Sensing

20. • Active Sensors provide their own energy source for illumination of the target by
directing a burst of radiation at the target and use sensors to measure how the target
interacts with the energy.
• Most often the sensor detects the reflection of the energy, measuring the angle of
reflection or the amount of time it took for the energy to return.
• Active sensors provide the capability to obtain measurements anytime, regardless of the
time of day or season.
• They can be used for examining energy types that are not sufficiently provided by the
sun, such as microwaves, or to better control the way a target is illuminated. However,
active systems require the generation of a fairly large amount of energy to adequately
illuminate targets.
• Doppler radar is an example of an active remote sensing technology.
Sensor Detection
Active detection

21. Active Remote
Sensing

22. • sensors measure levels of energy that are naturally emitted, reflected, or transmitted by
the target object.
• Passive sensors are those which detects naturally occurring energy. Most often, the
source of radioactive energy is the sun.
• Detection of reflected solar energy, for example, can only proceed when the target is
illuminated by the sun, thus limiting visible light sensors on satellites from being used
during a nighttime pass.
• The Thematic Mapper, the primary sensor on the Landsat satellites, is a good example of
a passive sensor.
Sensor Detection
Passive detection

23. Sensor Detection
Passive detection

24. Active and Passive RS

25. • Aircraft
– Helicopters
– Microlites
– Low altitude aircrafts
– High altitude aircraft
• Satellites
– Orbiting satellites
– Geostationary satellites
Usual Platforms

26. 1. Various civil engineering application areas include
2. Urban/ Regional planning
3. Site investigation
4. Terrain mapping and analysis
5. Water resources engineering
6. Town planning and urban infrastructure development,
7. Transportation network analysis
8. Landslide analysis.
Regional Planning and Site Investigations: Site investigations in general
require topographic and geologic considerations. Remote sensing data
permits such an assessment.
In case of dam site investigation, information on topography is essential.
Geological consideration involves the different soil and rock types and
physical properties
e sourc
Application of Remote Sensing in
Civil Engineering

27. In selecting river-crossing sites for bridges and pipelines,
An important consideration is the stability of slopes leading
down to and up from the water crossing. Such slopes include
riverbanks, terrace faces and valley wall. History of river
erosion and sedimentation would give clues needed for
locating the sites where scour is likely to occur. High spatial
resolution satellite data with stereo vision capability can
facilitate depth perception in the above said investigations
and also for regional planning of large commercial airports,
harbors, industrial towns and recreational sites.
Application of Remote Sensing in
Civil Engineering

28. • Hydro geological and geomorphologic information along with
geological structures derived from satellite data are very useful in
sitting the ground – water bore holes.
• Terrain Mapping and Analysis Assessment of the performance
of the terrain for specific developmental activities can be made
through terrain evaluation. For this, terrain information can be
acquired from RS data and by generating the Digital Terrain
Model
Application of Remote Sensing in
Civil Engineering

29. • In engineering construction like dam, the knowledge of
material comprising the terrain is essential for proper
planning, location, construction and maintenance of
engineering facilities.
• For computation of hydrograph parameters like peak runoff
rate, time of concentration and time to peak, the height and
slope information derived from Digital Elevation Model
(DEM) are useful.
• In large area reconnaissance studies, various technically
feasible and economically viable alternatives in locating surplus
flow diversion routes to water deficient basins can be arrived at.
Application of Remote Sensing in
Civil Engineering

30. • projects of large dimensions require considerations of land
use / land cover, soil and geological mapping, terrain
evaluation, construction material inventory etc. the latter are
derived from satellite remote sensing data of particular
resolution depending upon the scale on which such
information is required
Application of Remote Sensing in
Civil Engineering

31. • Provides a view for the large region
• Offers Geo-referenced information and digital information
• Most of the remote sensors operate in every season, every
day, every time and even in real tough weather
• Easy acquisition of data over inaccessible areas
• A single data can be used for differentuses
Advantages of Remote Sensing

32. • Remote sensing requires trained and experienced personnel
for data processing and analysis
• It becomes expensive affair if applied for a small area
particularly for one-time analysis
• Software used for processing the data are costly
• Any interpretation based solely on remotely sensed data
should be used with caution unless supported by ground
verification
Disadvantages of Remote
Sensing

33. Resolution