remote sensing By:-priyanshu kumar

1. Medi-Caps Institute of Science and Technology
Department of Civil Engineering
Topic: - Remote Sensing
Submitted To: -
Mr. Sagar Patni
(Assistant Professor)
submitted by:-
priyanshu kumar

2. ACKNOWLEDGEMENT
First and foremost I want to express my heartiest gratitude to almighty god who has been continuous source of
inspiration and strength that help me way in accomplishment of this endeavor.
I would like to express a deep sense of gratitude to Mr. Sagar Patni, Assistant Professor, Civil Engineering
Department, Medi-Caps Institute of Science and Technology, Indore for the valuable guidance and inspiration
throughout for the dissertation work. I am thankful for his innovative ideas and enthusiasm which led to
successful completion of this work. I also want to show my gratitude to all whose insight helped me to complete
this project.
I pay special thanks to my groups for their support, cooperation and suggestion during the study period.
All may not have been mentioned but none has been forgotten.

3. CONTENTS
 Introduction
 History
 Type of Remote Sensing
 Principle of Remote Sensing
 Stages in Remote Sensing
 Application
 Indian Remote Sensing
 Advantages and Disadvantages

4. INTRODUCTION
Remote sensing is the acquisition of information about an object or phenomenon without making physical
contact with the object and thus in contrast to on site observation. Remote sensing is used in numerous fields,
including geography and most Earth Science disciplines (for example, hydrology, ecology, oceanography,
glaciology, geology); it also has military, intelligence, commercial, economic, planning, and humanitarian
applications. In current usage, the term generally refers to the use of aerial sensor technologies to detect and
classify objects on Earth (both on the surface, and in the atmosphere and oceans) by means of propagated
signals (e.g. electromagnetic radiation).

5. HISTORY OF REMOTE SENSING
The modern discipline of remote sensing arose with the development of flight. The balloonist G. Tourna chon
(alias Nadir) made photographs of Paris from his balloon in 1858. Messenger pigeons, kites, rockets and
unmanned balloons were also used for early images. With the exception of balloons, these first, individual
images were not particularly useful for map making or for scientific purposes.
Systematic aerial photography was developed for military surveillance and reconnaissance purposes beginning
in World War I and reaching a climax during the Cold War with the use of modified combat aircraft such as
the P-51, P-38, RB-66 and the F-4C, or specifically designed collection platforms such as the U2/TR-1, SR-71,
A-5 and the OV-1 series both in overhead and stand-off collection. A more recent development is that of
increasingly smaller sensor pods such as those used by law enforcement and the military, in both manned and
unmanned platforms. The advantage of this approach is that this requires minimal modification to a given
airframe. Later imaging technologies would include Infra-red, conventional.
The development of artificial satellites in the latter half of the 20th century allowed remote sensing to progress
to a global scale as of the end of the Cold War. Instrumentation aboard various Earth observing and weather
satellites such as Landsat, the Nimbus and more recent missions such as RADARSAT and UARS provided
global measurements of various data for civil, research, and military purposes. Space probes to other planets
have also provided the opportunity to conduct remote sensing studies in extraterrestrial environments, synthetic
aperture radar aboard
the Magellan spacecraft provided detailed topographic maps of Venus, while instruments aboard SOHO
allowed studies to be performed on the Sun and the solar wind, just to name a few examples

6. TYPES OF REMOTE SENSING
There are two types of remote sensing instruments
1. Passive
2. Active
1. Passive instruments detect natural energy that is reflected or emitted from the observed scene. Passive
instruments sense only radiation emitted by the object being viewed or reflected by the object from a source
other than the instrument. Reflected sunlight is the most common external source of radiation sensed by
passive instruments. Scientists use a variety of passive remote sensors.
 Radiometer
An instrument that quantitatively measures the intensity of electromagnetic radiation in some band of
wavelengths in the spectrum.
 Imaging Radiometer a radiometer that includes a scanning capability to provide a two-dimensional array
of pixels from which an image may be produced is called an imaging radiometer.
 Spectrometer
a device designed to detect, measure, and analyze the spectral content of the incident electromagnetic
radiation is called a spectrometer.
1. Active instruments provide their own energy (electromagnetic radiation) to illuminate the object or scene
they observe. They send a pulse of energy from the sensor to the object and then receive the radiation that
is reflected or backscattered from that object. Scientists use many different types of active remote sensors.
 Radar (Radio Detection and Ranging) A radar uses a transmitter operating at either radio or microwave
frequencies to emit electromagnetic radiation and a directional antenna or receiver to measure the time of
arrival of reflected or backscattered pulses of radiation from distant objects.
 Scatterometer
A Scatterometer is a high frequency microwave radar designed specifically to measure backscattered
radiation. Over ocean surfaces, measurements of backscattered radiation in the microwave spectral region
can be used to derive maps of surface wind speed and direction.

7.  Lidar (Light Detection and Ranging) A LIDAR uses a laser (light amplification by stimulated emission of
radiation) to transmit a light pulse and a receiver with sensitive detectors to measure the backscattered or
reflected light.
 Laser Altimeter a laser altimeter uses a LIDAR (see above) to measure the height of the instrument
platform above the surface. By independently knowing the height of the platform with respect to the mean
Earth's surface, the topography of the underlying surface can be determined.

8. PRINCIPLE OF REMOTE SENSING
Detection and discrimination of objects or surface features means detecting and recording of radiant energy
reflected or emitted by objects or surface material (Fig. 1). Different objects return different amount of energy in
different bands of the electromagnetic spectrum, incident upon it. This depends on the property of material
(structural, chemical, and physical), surface roughness,
Angle of incidence, intensity, and wavelength of radiant energy. The Remote Sensing is basically a multi-
disciplinary science which includes a combination of various disciplines such as optics, spectroscopy,
photography, computer, electronics and telecommunication, satellite launching etc. All these technologies are
integrated to act as one complete system in itself, known as Remote Sensing System. There are a number of stages
in a Remote Sensing process, and each of them is important for successful operation.

9. STAGE OF REMOTE SENSING
 Emission of electromagnetic radiation, or EMR (sun/self- emission)
 Transmission of energy from the source to the surface of the earth, as well as absorption and scattering
 Interaction of EMR with the earth’s surface: reflection and emission
 Transmission of energy from the surface to the remote sensor
 Sensor data output.

10. APPLICATION
1. Radar is mostly associated with aerial traffic control, early warning, and certain large scale
meteorological data. Doppler radar is used by local law enforcements’ monitoring of speed limits and in
enhanced meteorological collection such as wind speed and direction within weather systems in addition
to precipitation location and intensity. Other types of active collection includes plasmas in the
ionosphere. Interferometric synthetic aperture radar is used to produce precise digital elevation models
of large scale terrain (See RADARSAT, TerraSAR-X, Magellan).
2. Laser and radar altimeters on satellites have provided a wide range of data. By measuring the bulges of
water caused by gravity, they map features on the seafloor to a resolution of a mile or so. By measuring
the height and wavelength of ocean waves, the altimeters measure wind speeds and direction, and
surface ocean currents and directions.
3. Ultrasound (acoustic) and radar tide gauges measure sea level, tides and wave direction in coastal and
offshore tide gauges.
4. Light detection and ranging (LIDAR) is well known in examples of weapon ranging, laser illuminated
homing of projectiles. LIDAR is used to detect and measure the concentration of various chemicals in
the atmosphere, while airborne LIDAR can be used to measure heights of objects and features on the
ground more accurately than with radar technology. Vegetation remote sensing is a principal application
of LIDAR.
5. Radiometers and photometers are the most common instrument in use, collecting reflected and emitted
radiation in a wide range of frequencies. The most common are visible and infrared sensors, followed by
microwave, gamma ray and rarely, ultraviolet. They may also be used to detect the emission spectra of
various chemicals, providing data on chemical concentrations in the atmosphere.
6. Stereographic pairs of aerial photographs have often been used to make topographic maps by imagery
and terrain analysts in traffic ability and highway departments for potential routes, in addition to
modelling terrestrial habitat features.
7. Simultaneous multi-spectral platforms such as Landsat have been in use since the 70’s. These thematic
mappers take images in multiple wavelengths of electro-magnetic radiation (multi-spectral) and are
usually found on Earth observation satellites, including (for example) the Landsat program or the
IKONOS satellite. Conventional Maps of land cover and land use from thematic mapping can be used to
prospect for minerals, detect or monitor land usage, detect invasive vegetation, deforestation, and
examine the health of indigenous plants and crops, including entire farming regions or forests. Landsat
images are used by regulatory agencies such as KYDOW to indicate water quality parameters including

11. Secchi depth, chlorophyll a density and total phosphorus content. Weather satellites are used in
meteorology and climatology.
8. Hyperspectral imaging produces an image where each pixel has full spectral information with imaging
narrow spectral bands over a contiguous spectral range. Hyperspectral imagers are used in various
applications including mineralogy, biology, defense, and environmental measurements.

12. REMOTE SENSING
The satellite for earth observation (SEO), now called bhaskara was 1
st
Indian remote sensing satellite.
Construction of Indian satellite began 1973 by ISRO and launched by a soviet launch vehicle from USSR into
near circular orbit in June 1979.
The satellite a weighing about 440kg was polyhedral in shape with 26 flat faces and measured approximately
1.4m end end.
Following the successful demonstration flights of Bhaskhar and Bhaskara-2 satellites launched in 1979 and
1981, respectively, India began to develop the indigenous Indian Remote Sensing (IRS) satellite program to
support the national economy in the areas of agriculture, water resources, forestry and ecology, geology, water
sheds, marine fisheries and coastal management.
The sensors on Bhaskara satellite are two television camera's three microwave radiometers and a data collection
platform.
The 1
st
two IRS spacecraft IRS-1A (March 1988) & IRS-1B (august 1991) were launched by Russian Vostro
booster from Bikaner commodore.
IRS -1A is failed in 1992, while IRS-1B continued to operate through 1999.
INDIAN REM

13. IRS DATA APPLICATION
Space Based Inputs for Decentralized Planning (SIS-DP).
National Urban Information System (NUIS).
ISRO Disaster Management Support Programmer (ISRO-DMSP).
Biodiversity Characterizations at landscape level.
Preharvest crop area and production estimation .of major crops.
Drought monitoring and assessment based on vegetation condition.
Flood risk zone mapping and flood damage assessment.
Hydro-geomorphological maps for locating underground water resources for drilling well.
Irrigation command area status monitoring.
Snow-melt run-off estimates for planning water use in downstream projects
Land use and land cover mapping
Urban planning
Forest survey
Wetland mapping
Environmental impact analysis
Mineral Prospecting
Coastal studies
Integrated Mission for Sustainable Development (initiated in 1992) for generating locale-specific
prescriptions for integrated land and water resources development in 174 districts

14. ADVANTAGES OF REMOTE SENSING
1. The major advantages of remote sensing over ground based methods are
2. Synoptic view: It facilitates the study of various features of earth surface in their spatial relation to each
other & helps to delineate the required features & phenomenon.
3. Accessibility: It makes it possible to gather information about inaccessible areas where it is not possible
to gather information through ground surveys.
4. Time: These techniques save time & efforts as information about large area can be gathered quickly.
5. Multidisciplinary applications: Remote sensing data are useful to different disciplines such as geology,
fisheries, forestry, land use etc.
6. Satellite images are permanent records, providing useful information in various wavelengths.
7. Large area coverage enables regional surveys on a variety of themes and identification of large features.
8. Repetitive coverage allows monitoring of dynamic themes like water, agriculture etc.
9. Easy data acquisition at different scales and resolutions.
10. A single remotely sensed image can be analysed and interpreted for different purposes and applications.
11. Amenability of remotely sensed data for fast processing using a computer.
12. Remote Sensing is unobstructive if the sensor is passively recording the electromagnetic energy reflected
from or emitted by the phenomena of interest.
13. Thus, passive remote sensing does not disturb the object or area of interest.
14. The images are analysed in the laboratory thus reducing the amount of field work.

15. DISADVANTAGES OF REMOTE SENSING
1. Expensive to build and operate!!!!
2. Measurement uncertainty can be large
3. resolution is often coarse
1. 88D pulse volume is over 1.5 km wide at 100 km range from radar
2. satellites
4. Data interpretation can be difficult
1. need to understand theoretically how the instrument is making the measurements
2. need to understand measurement uncertainties
3. need to have some knowledge of the phenomena you are sampling
1. Expensive for small areas, particularly for one time analysis.
2. Requires specialized training for analysis of images.
3. Large scale engineering maps cannot be prepared from satellite data.
4. Aerial photographs are costly if repetitive photographs are required to study the dynamic features.
5. Human beings select the most appropriate sensor to collect the data, specify the resolution of the data,
calibrate the sensor, and select the platform that will carry the sensor, determine when the data will be
collected and specify how the data will be processed.
6. Thus, human method produced error may be introduced.
7. Powerful active remote sensing system, such as radars or lasers that emit their own EMR (electromagnetic
radiation), can be intrusive and affect the phenomenon being investigated.
8. Remote Sensing instruments often become uncalibrated, resulting in uncalibrated remote sensing data.
Distinct phenomena can be confused if they look the same to the sensor, leading to classification error.
Example: artificial & natural grass in green light (but infrared light can easily distinguish them).
9. Phenomena which were not meant to be measured (for the application at hand) can interfere with the
image and must be accounted for. Examples for land cover classification: atmospheric water vapour, sun
vs. shadow (these may be desirable in other applications).