Transcript
1
A Presentation By : Mandeep MSc. Final (Env. Scs.)
Contents of Presentation
1. Introduction to Satellites and their types 2. India’s Earth Observation Programme 3. Brief Introduction to Foreign Space Tech. 4. Trends in Tech. 5. Geo-Informatics : a) RS b) GIS c) GPS d) ICT 6. Photo-Interpretation 7. Apps. of RS & GIS in Various Fields 8. Apps. of RS & GIS in Environmental Management
1. Satellites and their types
What is Satellite ?
Heavenly or artificial body revolving round a planet e.g. Heavenly Body-Moon Artificial Body-Man made Satellite Types: 1. Geostationary Satellite (communication) 2. Polar Sun Synchronous Satellite (Remote Sensing)
Geostationary Satellite
Sun-synchronous Satellite
Satellite Orbits
Sun-synchronous satellite
TYPES OF SATELLITES Astronomical satellites : Used for study of distant celestial objects and outer space. Communications satellites : For communications/ Broadcasting Miniaturized satellites : Low weights and small sizes.
Minisatellite : 500–100 kg Microsatellite : 100-10 kg Nanosatellite : >10 kg Navigational satellites : Uses for radio time signals transmitted to enable mobile receivers on the ground to determine their exact location in real time, i.e. GPS, GLONASS, GALILEO, COMPASS Reconnaissance satellites : Earth observation satellite or communications satellite deployed for military or intelligence applications. Very little is known about the full power of these satellites Earth observation satellites : Satellites intended for non-military uses such as environmental monitoring, meteorology, map making etc. Weather satellites : Used to monitor Earth's weather and climate Anti-satellites weapons : Satellites that are designed to destroy enemy warheads, satellites, other space assets. Space stations : Orbital structures that are designed for human beings to live on in outer space.
2. India’s Earth Observation Programme
Dr. Vikram Sarabhai (1919-1971)
The Architect of Indian Space Programme
Capsule of Wisdom:
“He who can listen to music in the midst of noise can achieve great things”
Indian Space Programme – the Initial Days
World Class
Launch Facilities
Indian Space Programme – the Initial Days to Today
2001: Successful flight test of GSLV
2002: Launch of METSAT (renamed Kalpana) by PSLV.
2003: Launch of RESOURCESAT-1, Launch of third generation INSAT-3A
2004: Successful Ist operational flight of GSLV. EDUSAT launched
2005: CARTOSAT-1 launched
2007: CARTOSAT-2 launched
2008: Launch of CARTOSAT-2A along with 10 satellites onboard PSLV C-9
• Chandrayaan-1 Launched
2009: Oceansat-2 and Risat-2 launched.
2010: Cartosat-2B launched
2011: Resourcesat-II launched, Megha-Tropics Launched
2012: RISAT-I launched
• 2013 : Mangalyaan Launched, IRNSS-1A Launched, GSAT-7 with cryogenic engine launched
• 2014 : IRNSS-1B Launched, SPOT-7 launched, Mangalyaan inserted in Mars Orbit
Recent satellites launched
2013(25 Feb) SARAL 2013( 1 July) IRNSS-1A 2013(26 July) INSAT-3D 2013(30 August) GSAT-7 2013( 5 Nov) MOM(Mars Orbiter Mission) 2014 (5 Jan) GSAT-14(capacity of Extended C and Ku-band) 2014 (4 April) IRNSS-1B 2014(10 Nov) IRNSS-1C 2014(7 Dec) GSAT- 16(48 transponder) 2015 (28 March) IRNSS-1CD
1. Indian Space Research Organization (ISRO): Bangalore
2. Space Applications Centre (SAC) : Ahmedabad 3. Vikram Sarabhai Space Centre (VSSC):
Thiruvananthapuram 4. National Remote Sensing Agency (NRSA):
Hyderabad
5. Indian Institute of Remote Sensing (IIRS): Dehradun
6. Satish Dhawan Launching Centre : Sriharikota 7. INSAT Master Control Facility: Hasan 8. North-Estern Space Application Centre (NE-SAC): Shillong 8. Regional Remote Sensing Centres (RRSCs) Dehradun Jodhpur Nagpur Bangalore Kharagpur
LAUNCH VEHICLE FAMILY
SOUNDING ROCKET-1972
SLV,17T,40Kg,LEO-1979
ASLV,39T,150Kg.LEO-1987
PSLV,275T,1000Kg,POLAR-1993
GSLV,402T,2500Kg,GTO-2001
INSAT & GSAT INSAT
The Indian National SATellite system is a series of multipurpose geo-stationary satellites launched by ISRO to satify the telecommunications, broadcasting, meteorology, search and rescue operations.
Commissioned in 1983 is the largest domestic communication system in the Asia pacific region.
It is a joint venture of the DOS, Deptt. Of telecomm., IMD, AIR, and Doordarsan.
GSAT
The GSAT (Geosynchronous Satellites) satellites are india’s indigenously developed technologies of comm. Satellites, used for digital audio, data and video broadcasting.
As of Aug. 2015, 12 GSAT Satellites have been launched by ISRO.
Recently on Aug 27 ,2015 GSLV successfully launches India’s latest communication satellite GSAT-6
Towards Thematic Satellites : Recent Emphasis
OCM & MSMR
Resourcesat-1
Metsat-1
Edusat
Oceansat-1
Cartosat-1
INSAT – 4A
AWiFS, LISS 3
& LISS 4
Fore & AFT PAN 6 Ku &
6 Ext C
VHRR & DRT
12 C &
12 Ku High resolution & Multi-spectral
Along-track Stereo & DEM
Multiband & hyperspectral Towards mesoscale weather
modeling
DTH: Reaching the homes
Virtual Schools & Universities
AWS DWR
Addressing
Societal
Needs
RISAT-1
C-band SAR; 3-50 m
Multi-Pol; Multi mode
Launch : PSLV-C5, 17 Oct. 2003/ 20 May, 2011
APPLICATIONS POTENTIAL
• Natural resources census
• Improved crop discrimination
• Vegetation dynamics
• Crop yield
• Disaster management support
• Forestry and biodiversity etc.
Mission Life : 5 Yrs
Mass of S/C : 1350 kg (at Lift-off)
Orbit : 817 km; Sun-synchronous
Payloads : LISS- 3, LISS- 4 & AWiFS
Spatial Res. : 23.5m 5.8 m 56 m
Repetitivity : 24 days for LISS-3
5 days for AWiFS
Revisit : 5 days for LISS-4
(with 26 Deg. Tilt)
Resourcesat – I &II
• 2.5 m resolution, 30 Km Swath
• Stereo mission; +26° / -5°
forward/ Aft view
• Revisit : 5 days
• Along Track Stereo viewing -
first of its kind in the world
Cartosat-1&2
• Large Scale Cartographic maps
• Cadastral level Thematic maps
• National Digital Elevation Model
• Rural Development
• Urban infrastructure & utility planning
Launch : PSLV-C6: May 05, 2005
APPLICATIONS POTENTIAL
Trans Lunar
Injection
Mid Course Correction
GTO
ETO
Lunar Transfer
Trajectory
Initial Orbit
~ 1000 km
Lunar Insertion
Manoeuvre
Final Orbit
100 km Polar
ASTROSAT
Moon at Launch
To achieve 100 x 100 km Lunar Polar Orbit.
PSLV to inject 1050 kg in GTO of 240 x 36000 km.
Lunar Orbital mass of 523 kg with 2 year life time.
Scientific payload 55 kg.
Expanding the scientific knowledge about the Moon; Upgrading our technological
capability; Providing challenging opportunities for planetary research
Chandrayaan – 1:
Indian Observatory
in Space
Beyond the Earth…
Multiwavelength Observatory
Payloads
TMC: Terrain Mapping
Camera (PAN; Stereo;
5m; 40km)
HySI: Hyperspectral
imager (400-900 nm;
15nm; 80m; 40km)
LLRI: Lunar Laser
Ranging Instrument (10
height res.)
LEX: Low Energy X-
ray spectrometer
(10km footprint)
HEX: High Energy X-
ray spectrometer
(20km footprint) to
study radioactive
elemetns.
1. Atmospheric studies:
i. Lyman-Alpha Photometer (LAP): a photometer that measures the ratio of deuterium and hydrogen in the upper atmosphere which will help in estimating the amount of water loss to outer space. ii. Methane Sensor for Mars (MSM): It will measure methane in the atmosphere of Mars, if any, and map its sources. 2. Surface imaging studies i. Thermal Infrared Imaging Spectrometer (TIS) — will measure the temperature and emissivity of the Martian surface, allowing for the mapping of surface composition and mineralogy of Mars. ii. Mars Color Camera (MCC) — will provide images in the visual spectrum, providing context for the other instruments.
Future Indian EO Missions
RESEOURCESAT-3: Increased resolution and more spectral bands:
Sensor : AWiFS 25 m reolution, 600 km swath. LISS-III-WS, 23.5 m resolution, 2 additional bands, Wide Swath LISS-IV at 5.8m with 1 additional band, 25km swath Addition of new sensors with 25km swath: LISS-V (PAN) at 2.5m resolution Hyperspectral at 25m resolution (~200 Bands) 5 day revisit cycle
RESEOURCESAT-4: Addition of new sensors with 12.5 km swath
Sensor: LISS-IVn at 2.5m, 3-4 bands, 5 day revisit LISS-Vn at 1.25m PAN, 5 day revisit HISn at 12.5m, 200 bands, 5 day revisit
CARTOSAT-3: Increased resolution and more spectral bands:
Sensors: PAN at 0.5m resolution MSI at 2-4m, 4 bands HSI at 8m, ~200 bands Swath at 8-10km
OCEANSAT-3: Sensor : Thermal IR Sensor, 12 channel Ocean Color Monitor, Scatterometer and Passive Microwave Radiometer. Uses : Potential Fishing Zones. Ocean biology and Sea state applications
3. Brief introduction to Foreign Space Tech.
International Space Agencies
India ISRO USA NASA Russia ROSCOSMOS Japan JAXA France CNES China CNSA EU ESA Germany DLR
Major Foreign R. S. satellites
Satellite Sp. Resolution Country (meters) NOAA 1100 USA Landsat (5,7,8) USA Multispectral Scanner (MSS) 80 Thematic Mapper (TM) 30 Enhanced TM (ETM) 20 SPOT 10/20 French RADARSAT 30-50 Canada (Microwave) IKONOS 1.0/4.0 Space Imagine, USA (Now GeoEye) Quick Bird 0.6/2.5 Digital Globe, USA Word View-I 0.5 m PAN Digital Globe, USA (2007) stereo GeoEye-1 0.4 m PAN GeoEye, USA 2008 1.6 m Mxl Word View-II 0.5 m PAN Digital Globe, USA (2009) 1.84 m Mxl Word View-III 0.31 m PAN Digital Globe, USA (2014) 1.24 m Mxl
3.70 m SWIR
4. Trends in Technology
Aerial
Photography
Satellite
Remote
Sensing
Image
Interpretation
Satellite
Remote Sensing
& Digital Image
Processing
Satellite
Remote Sensing
& Geographic
Information
System (GIS)
Satellite
Remote
Sensing
GIS & Global
Positioning
System
Satellite
Remote
Sensing
GIS, Global
Position System,
Web
communication
& Virtual World
1975-1990 1990-1995 1995-2000 2000-20005 2005 - Beyond 1960-1975
Trends in Technology
Topographic
Mapping
Thematic
Mapping
Widening of
Thematic
Disciplines
Integration of
Thematic
Information
Spatial
Modelling
Decision
Support
System
Geosciences
Forestry
Soils
Water
Resources
Oceanography
Marine Science
Agriculture
Fisheries
Biodiversity
Drinking
Water
Geomorphology
…...-1975 1970-1980 1980-1990 1990-1995 1990- …. Future trends
Biodiversity
Prioritisation
Modeling
Landslide
Hazard
Zonation
Modeling
Infrastructure
Management
Natural
Resource
Management
Strategic
Planning
Land
Management
and Reform
Trends in Application
5. Geo-Informatics
EOS AM-1 in orbit
GEO-INFORMATICS RS
GIS
GPS
Geographic Information System (GIS), Remote Sensing (RS), Global Position System (GPS) and Information & Communication Technology (ICT) which help in acquiring and analyzing information about the Earth and its resources in spatial format
ICT
• ‘Remote’ means far away and ‘Sensing’ means believing or observing or acquiring some information.
• Remote sensing means acquiring information of things from a distance.
• Three out of five senses uses RS : 1. EYE (sense of sight) 2. EAR(sense of hearing) 3. NOSE(sense of smell) • While other two require physical contact 1. Sense of Touch 2. Sense of taste
Remote Sensing is the Science(and to some extant, art) 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, analysing,and applying that information.
Remote Sensing(RS)
Receiving station processing Archiving
Distribution
PRINCIPLE OF REMOTE SENSING
PRINCIPLE OF REMOTE SENSING
A. Energy Source or Illumination B. Radiation and the Atmosphere C. Interaction with the Target D. Recording of Energy by the Sensor E. Transmission, Reception and Processing F. Interpretation and Analysis G. Application
• Active sensor
– Throws energy on the target object & senses the reflected energy
• Camera with flash
• RADAR
• Passive sensor
– No personal source of energy (Sun is the only source); senses energy reflected/ emitted by the target
• Camera without flash
• Human eye, ear, nose
Active and Passive Remote Sensing
WAVE CONCEPT OF EMR
C = ν λ
Electromagnetic energy forms the basic source for remote sensing observations. Sun is the universal source of electromagnetic energy.
The electromagnetic spectrum is the form of arrangement of electromagnetic energy either in the form of wavelength or in frequency.
The basic relation is
E=MC2
C=υ λ
υ= Frequency; λ = Wavelength ; C = Velocity of Light
E= Energy; M = Mass of Particle
ELECTOMAGNETIC SPECTRUM
Violet: 0.400 - 0.446 µm Primary Colours: Blue: 0.446 - 0.500 µm Red, Green, Blue Green: 0.500 - 0.578 µm Yellow: 0.578 - 0.592 µm Orange: 0.592 - 0.620 µm Red: 0.620 - 0.700 µm
• Black Body : that absorbs all incident
Radiations
• White Body : that Reflects all
Incident Radiations
• EARTH acts as a Gray Body
Thermal Sensing
Reality is the perceived Truth
Visible Sensing
Radiations is very sensitive to temp. of Body
Particles and gases in the atmosphere can affect the incoming light and radiation. These effects are caused by
1. Scattering Rayleigh scattering occurs when particles are very small compared to the
wavelength of the radiation. These could be particles such as small specks of dust or nitrogen and oxygen molecules.
Mie scattering occurs when the particles are just about the same size as the wavelength of the radiation. Dust, pollen, smoke and water vapour are common causes of Mie scattering which tends to affect longer wavelengths than those affected by Rayleigh scattering.
Nonselective scattering. This occurs when the particles are much larger than the wavelength of the radiation. Water droplets and large dust particles can cause this type of scattering.
2. Absorption Ozone, Carbon dioxide, and Water Vapour are the three main atmospheric
constituents which absorb radiation. 3. Reflection: Some radiations are reflected back to atmosphere from clouds, aerosoles and
water droplets.
INTERACTION WITH ATMOSPHERE
Energy Interaction Mechanism
Interaction with the Target
Specular Reflection Diffused Reflection
SPECTRAL REFLECTANCE OF VARIOUS OBJECTS
Atmospheric Windows
______________________________________ λ (µm) Spectral region ______________________________________ 0.3-1.3 VIS-NIR 1.5-1.8 MIR 2.0-2.6 3.0-3.6 4.2-5.0
7.0-15.0 TIR __________________________________________
ATMOSPHERIC WINDOWS
Components of Remote Sensing
• Platform
– The vehicle/device on which sensors are mounted
• Sensor System
– The device which senses the energy reflected/emitted by the target object
• Data Products
– Information received from the sensor Packaged as per user requirement
PLATFORMS
• Remote sensing is essentially studying
interaction of electro-magnetic radiation
with different objects – land, water,
atmosphere, etc.
• Understanding properties of EM radiation
under various conditions is fundamental
to understanding of remote sensing,
both from technology and application
point of view.
Data Representation
Data Products
• Satellite data products are available from the data suppliers i.e. NRSC in India
• Data is available based upon the user requirements
• Type
– Digital data for processing by Computer
– Photographic prints for visual interpretation
i.e. Hardcopies, Negatives, Dia-positives
Characteristics of Data Products
• Area Covered
• Date & Time of acquisition
• Level of Processing
– Raw
– Corrected for Radiometric errors
• Line drop outs, sensor malfunctions
– Corrected for Geometric errors
– Special Products (Merged/enhanced/image maps)
Interpretation of Remotely Sensed Information
• Concept of signature – A combination of characteristics of the objects by
which we can identify it on remote sensing data
– The characteristics are manifested in terms of shape, size, tone, texture (frequency of tonal change, pattern (spatial arrangement of objects), context / association etc on the image
– Based on our prior knowledge – identify the characteristics to be used as signature
– Associate signature with objects : develop Interpretation key
Panchromatic Image: is the one that captures the image across large part of the electromagnetic spectrum. It is a single band image in gray scale. Multi-spectral Image: is one that captures image data at specific frequencies across the electromagnetic spectrum. Multi-band (>3 bands) image data is in gray scale and any three bands can be used to create a coloured image. Hyper-spectral Image: is one that captures image data at very small frequency intervals across the electromagnetic spectrum. It contains data in numerous bands.
PREPARATION OF TCC AND FCC
EM bands Assigned
Colour
Blue Blue
Green Green TCC
Red Red
NIR
Blue Blue
Green Green FCC
Red Red
NIR
True and false Color Photography
Resolution
Resolution is defined as the ability of the system to provide the information at the smallest discretely separable quantity, in terms of area (spatial), wavelength band of EMR (spectral), radiation quantity (radio-metric) and time (temporal)
PIXEL and Resolution • The PIXEL (a word invented from “picture element”) is
the basic unit of programmable color on a computer display or computer image.
• The following slide has the same photo at three resolutions.
• Remember this doesn’t change the size in terms of the number of pixels which is the true measure of resolution, it just changes the physical size of the photo.
• I am assuming a screen or projector size of 800 x 600 pixels.
• The image in the top third of the slide is the correct size for this application, It’s 800 pixels wide by 200 pixels high.
• The middle third, the number of pixels has been reduced by half in both dimensions, to 400 pixels by 100 pixels.
• The bottom third, the number of pixels has been reduced again by half in both dimensions, to 200 pixels by 50 pixels.
• The top picture which matches the resolution of the output device exactly gives the best image.
• On the screen their resolution in dots per inch is somewhat irrelevant, since that depends on the size of the monitor or projected image. As long as I get the number of pixels right, I’ll have the best image quality available.
2.5 x 10 inches at
80 dots per inch
2.5 x 10 inches at 40 dots per inch
2.5 x 10 inches at
20 dots per inch
Spatial resolution Scanner’s spatial resolution is the smallest ground segment sensed at any instant. It is also called ground resolution element or pixel.
LISS III G, R, IR 23.5 m MIR 70.5 m LISS IV G, R, IR 5.8 m
WiFS R, IR 188 m AWiFS G, R, IR 58 m
Cartosat-I PAN 2.5 m Cartosat-II PAN 1.0 m
Spectral resolution Sampling the spatially segmented image in different spectral intervals, thereby allowing the spectral Irradiance of the image to be determined. m
PAN 0.50 - 0.75 LISS III Band 2 0.52 - 0.59 Band 3 0.62 - 0.68 Band 4 0.77 - 0.86 Band 5 1.55 - 1.70 Thermal Band 1 0.45-0.52 Mapper (TM) Band 2 0.52-0.60 Band 3 0.63-0.69 Band 4 0.76-0.90 Band 5 1.55-1.75 Band 6 10.40-12.50 Band 7 2.08-2.35 Enhanced TM Band 8 0.52-0.90 (in addition to TM)
Hyper-spectral Imaging MODIS 30 bands with 250 m-1 km spatial resolution,1900-2300 swath Hyperion 242 bands of 11 nm each in 400-2500 nm range and 30 m spatial resolution, 7.5 km swath
Radiometric resolution The number of different intensities of radiation the sensor is able to distinguish. Dividing the total range of the signal output of the sensor into a large number of just discriminable levels so as to be able to distinguish ground features differing only slightly in a radiance or reflectance. LISS III 7 bit / 128 levels (10 bit for R-II) AWiFS 10 bit / 1024 levels (12 bits for R-II) PAN 6 bit / 64 levels
Temporal resolution
Obtaining spatial and spectral data at certain time intervals. Temporal resolution is also called as the repetitivity of the satellite in case of satellites IRS 1A/1B 22 days IRS 1C/1D 24 days PAN 5 days
Advantages of Remote Sensing
• Synoptic View – Very large area at a glance
– Move mountains to your desktop
• Very Fast information acquisition – Timely & accurate information
• Repeated coverage
• Digital data amenable to computer processing
• Permanence of records
• Mapping of inaccessible areas
• Economical
to GIS : • The Geographic(al) information system consists
two different disciplines: geography and information system.
• Geography is the scientific study of geospatial pattern and process while information system refers to a system containing electronic records.
• The GIS is a computer- based information system used to digitally represent and analyse the geospatial data or geographic data
• Geographic Information System (GIS) is defined as an information system that is used to input , store, retrieve, manipulate, analyse, and output geographically referenced data or geospatial data, in order to support decision making for planning and management of land use, natural resources, environment, transportation, urban facilities, and other administrative records.
1-74
Defining GIS
• A Powerful tool for solving real-world problems
A method to
visualize, manipulate, analyze, and display spatial data
Key Components of GIS
Computer System
Harware Software
Procedure
Users Data
GIS
Hardware, Software and Procedure For capture, storage, processing, Analysis, display, etc.
Maps, aerial photographs, Satellite images, statistic Tables, etc.
Design of standards, updating, Analysis and implementation
GPS- Global Positioning System
GPS is a satellite-based system, operated and
maintained by the U.S. Department of Defense (DoD),
that provides accurate location
and timing information to
people worldwide.
The system transmits radio
signals that can be used by GPS receivers to
calculate position, velocity and time
anywhere on earth, any time of
day or night, in any kind of
weather.
The NAVSTAR GPS concept was
developed in the early 1970's to meet
the U. S. military’s need for improved
navigation and positioning. The first Block I GPS satellite
was launched in 1978 and Full Operational
Capability (FOC) was achieved in 1994.
GPS Segments
The GPS consists of 3 segments:
1. Space
2. Control
3. User
Space Segment • The space segment is the satellite constellation,consisting
of 24 or more satellites.
• There are four satellites in each orbit plane
• The high altitude insures that satellite orbits are stable, precise and predictable, and that the satellites' motion through space is not affected by atmospheric drag.
• It also insures satellite coverage over large areas.
• GPS satellites orbit around the earth, in contrast to TV satellites which are in geostationary orbits (they rotate with the earth).
• The GPS satellites cross over any point on the earth approximately twice per day.
Satellite characteristics
24 satellites in 6 orbital planes. Satellites complete an orbit in approx. 12 hours.
Black = visible satellites, Red = not visible, Green = sight lines
Global Positioning System (GPS)
Satellite Signals
• The radio signals travel at the speed of light: 300,000 km per second.
• It takes 6/100ths of a second for a GPS satellite signal to reach earth.
• C/A code (Coarse Acquisition code) is available to civilians as the Standard Positioning Service (SPS).
• SPS now provides average horizontal accuracy of 7.8 meters 95% of the time and average vertical accuracy of <= 15 meters.
• The Precise Positioning Service (PPS), available only to the military (and other authorized users), provides higher accuracy via the P code.
Control Segment
The control segment is operated by the U.S. Department of Defense (DoD) which tracks and maintains the satellites. The Department of Transportation (DoT) now has management responsibility, along with DoD.
Control Segment
User Segment
The user segment consists of both military and civilian users. Military uses of GPS include navigation, reconnaissance, and missile guidance systems. Civilian use of GPS developed at the same time as military use, and has expanded far beyond anyone's original expectations.
Examples of civilian GPS applications include :
The user segment consists of receivers that provide positioning, velocity and precise timing to users worldwide.
Civilian applications of GPS exist in almost every field, from surveying to transportation to natural resource management to agriculture.
1) GPS on a helicopter to identify the location of victims in search and rescue operations
2) GPS on a tractor/combine linked to a yield monitor to generate yield maps (precision farming)
3) GPS used for aircraft navigation or to mark where rangeland weedshave been sprayed,
4) GPS used for recreational sailing navigation
5) Emergency services response system: a combined GPS/GIS system used to dispatch emergency vehicles and find the quickest route to a destination (GPS is also being used for pizza delivery systems
6) GPS to help a backpacker navigate in the woods.
How Does GPS Work?
GPS satellites are constantly transmitting signals that contain orbit data and timing information. Receivers pick up those signals and use the information tocompute positions.
Note:
Receivers don’t send signals back to satellites, contrary to what manypeople think. They are receivers not transceivers
How Does GPS Work? GPS receiver calculates its position by measuring the distance to satellites (satellite ranging).
3 Distance Measurements
Other Global Navigation Satellite Systems
Global Navigation Satellite System (GNSS) is the standard generic term for
satellite navigation systems that provide autonomous geo-spatial positioning
with global coverage. A GNSS allows small electronic receivers to determine
their location (longitude, latitude, and altitude) to within a few metres.
• Global Positioning System (GPS) of USA
• GLONASS of Russia
• GALILEO of EU (under development)
• IRNSS of India (under development)
• COMPASS of China (under development)
Global Navigation Satellite Systems
(GNSS)
• ICT (Information and communication technology –or technologies) is an umbrella term that includes any communication device or application, encompassing : radio, television, cellular phones, computer and network, hardware and software, satellite systems and so on, as well as the various services and applications associated with them, such as videoconferencing and distance learning.
• ICTs are spoken of in a particular context, such as ICTS in education, health care etc.
6. Photo-Interpretation
Introduction to Photo-Interpretation • Unlike a map, features on an aerial photograph or
image are not generalized or symbolized.
• Air photos record all visible features on the earth’s surface from an overhead perspective.
• Although the features are visible, they are not always easily identificable.
• “the process of studying and gathering the information required to identify the various cultural and natural features is called Photo-Interpretation”
• With careful interpretation, air photos are an excellent source of spatial data for studying the Earth’s Environment.
• Photographic interpretation is “the act of examining photographic images for the purpose of identifying objects and judging their significance”
• This mainly refers to its usage in military aerial reconnaissance using photographs taken from reconnaissance aircraft.
• The most basic principle is the elements of image interpretation which are :
1. Location 2. Size 3. Shape 4. Shadow 5. Tone/color 6. Texture 7. Pattern 8. Height /Depth 9. Site /Situation/Association 10. Time 11. Stereo perspective • These are routinely used when interpreting an aerial photo or
analyzing a photo- like image.
Elements of Photo-Interpretation
1. Location : There are two primary methods to obtain precise location in the form of coordinates –
(i) Survey in the field using traditional surveying techniques or GPS instruments.
(ii) Collect remotely sensed data of object, rectify the image and then extract the desired coordinate information.
2. Size : The size of an object is one of the most distinguishing characteristics and one of the more imp. Element of interpretation. Most commonly length, width and perimeter are measured. It is the measure of the surface area
(e.g. single-lane vs. multi-lane highways)
3. Shape : the form of an object on an air photo helps in identifying the object. Regular uniform shapes often indicate a human involvement.
4. Shadow : A Shadow provides information about the object’s height, shape, and orientation (e.g. tree species)
5. Tone / Color : The color chacs. of an object, relative to other objects in the photo, are used to identify the feature (e.g. sand has a bright tone, while water usually has a dark tone; tree species can be determined by the color of their leaves at certain times of the year.
6. Texture : The physical chacs. of an object will change the way they appear in the photo (e.g. calm water has a smooth texture; a forest canopy has a rough texture);
7. Pattern : similar to shape, the spatial arrangement of objects (e.g. row crops vs. pasture) is also useful to identify an object and its usage.
8. Height / Depth :
Height and Depth also known as “elevation” and “bathymetry”, is one of the most diagnostic elements of image interpretation. This is bcoz any object, such as a building or electric pole that rises above the local landscape will exhibit some sort of radial relief. Also, objects that exhibit this relief will cast a shadow that can provide info as to its height or elevation.
A good example of this would be buildings of any major city
9. Site /Situation /Association : Associating the presence of one object with another, or relating it to its environment, can help identify the objects (e.g. industrial buildings often have access to railway sidings; nuclear power plants are often located beside large bodies of water);
10. Time : temporal chacs. of a series of photographes can be helpful in determining the historical change of an area (e.g. looking at a series of photos of a city taken in different years can help in determining the growth of suburban neighbourhoods.
11. Stereo Perspective : watching an area in stereo, or 3D, is imp. For determining the topographical relief of an area, as well as the height of objects such as trees and building.
Stereoscopic imagery is the result of overlap, which is the amount by which one photograph includes an area covered by a neighbouring photograph.
7. Applications of Remote Sensing and GIS in various Fields
• Water Resources
• Geosciences
• Land Use / Land Cover & Urban Studies
• Agriculture & Soils Forestry
• Oceanography & Coastal Zone Studies
• Integrated Studies
• Disaster Management
Research & Development
Capacity building
Disaster Support Centre
Operational Services
Geo-informatics Applications
Panchayat
Planning
Watershed
Space-based Services for
Community Outreach
Tele-medicine
Training
Tele-education Weather Drinking Water
Information
Village Resources Centre (VRC)
Major Areas of Applications • LAND-COVER AND LAND-USE : Land cover and Land
Use change, Land Cover Mapping • AGRICULTURE : Crop Type Mapping, crop monitoring
and crop damage assessment. • FORESTORY : clear-cut mapping and Deforestation , Species identification and type, burn mapping. • GEOLOGY : structural mapping and terrain analysis,
lineament extraction, geologic unit mapping • GEOMORPHOLOGY : alluvial/fluvial(flowing
water)plain, eolian plain,weathering ,erosion,etc • URBAN APPS • HYDROLOGY : flood delineation and mapping, soil
moisture, ground water prospectus and recharge
• MAPPING
• OCEANS AND COASTAL MONITORING : ocean features, ocean color and phytoplankton conc., oil spill detection, sea surface height, sea surface roughness, ship routing, sea ice
• MONITORING OF ATMOSPHERIC CONSTITUENTS
IN SHORT WE CAN SAY THAT FROM EARTH SURFACE TO HIGH ABOVE IN THE SKY THERE ARE WIDE APPS. OF RS&GIS
Apps. of RS & GIS in Environmental Management
Environmental Monitoring : (i) Pollution Monitoring (ii) EIA (iii) Resource Monitoring (iv) Climate Change Environmental Mapping : I. Ground water and surface water II. Forest mapping III. Land use and Land cover IV. Mineral Resources V. Energy Resources VI. Water Resources VII. Wildlife VIII.Urban Mapping
Environmental Management : 1) Resource conservation and management : a) Biological Resource Management : i. Forest management ii. Wildlife Management iii. Management of Wetlands and fresh water ecosystems. (2) Physical Resource Management : • Watersheds • Rivers • Lakes • Soil conservation • Wasteland management (3) Energy Management
Weather Forecasting
Flood Mapping
Detection of Paleochannels.
Change Detection by comparing with past records
Landslide Monitoring etc.
In short , RS & GIS has huge applications in each and every field of environment.
NIGHT ARRIVES BETWEEN EUROPE & AFRICA
SANDSTORM LEAVING NORTH AFRICA TOWARDS THE ATLANTIC – CANARY ISLAND.
GIBRALTAR STRAITS
BLACK SEA
RED SEA
Resourcesat: AWiFS images
AWiFS Scene
Area South of Sirsa FCC (May, 02) (Rawatsar, Rajasthan)
Resourcesat L-IV
HARSAC CPB
Town Park, Hisar
Hisar Jail-II
Karan Lake, Karnal
PARLIAMENT HOUSE
CANNAUGHT PLACE
RASTRAPATI BHAWAN
N. DELHI RAILWAY STATION
WORLD VIEW-1
Env. Scs.& Engg. Deptt,T.B.4,GJU
top related