Remote sensing systems pdf

In general, the word remote sensing is used for data collection from artificial satellites orbiting the earth and processing such data to make useful decisions. Hence, remote sensing can also be defined as the science and art of collecting information about an object, area or phenomenon from a far-off place without coming in contact with it. In simple terms the civil engineering applications can be divided into two groups: a human related b environment related, and remote sensing plays a vital role in providing required near-real.

Space Segment : The space segment consists of the satellites orbiting the earth at a very high attitude. Sensor system : Sensors are instruments which sense the objects on the surface of the earth and records them.

The sensors mounted on satellites called scanners scans the objects on the surface of the earth. A set of consecutive scan lines forms an image, which is sent back to the earth receiving stations called ground segments. Ground Segment : They are the stations put up on the ground surface to receive the signals sent from remote sensing satellites. The signals received from the satellites are converted to images and stored in digital format.

The images are to be processed to retrieve useful information. This process is called Image Processing. Since, different objects on the ground have different properties of absorbing, scattering, transmitting and reflecting the energy, the images formed due to reflected energy waves will be different for different objects.

Hence, a correlation is made between the images developed and the corresponding objects on the ground Ground Truth. Thereafter, such information is used to interpret the images directly for making useful decisions. Remote sensing is extensively used in India for weather forecasting. It is also used to warn people about impending cyclones.

It can be used to study deforestation, degradation of fertile lands, pollution in atmosphere, desertification, eutrophication of large water bodies and oil spillage from oil tankers. Remote sensing can be used to study damages caused by earthquakes, volcanoes, land slides, floods and melting of ice in polar regions. Many times remote sensing will be helpful to predict the occurrence of natural hazards.

Remote sensing data is helpful for updating existing geological maps, rapid preparation of lineament and tectonic maps, identifying the sites for quarrying the minerals and helpful in locating fossil fuel deposits. Remote sensing data is useful in obtaining up-to-date land use pattern of large areas at any given time and also monitor changes that occur from time to time.

This information is used by regional planners and administrators to frame policy matters for all round development of the region. Civil engineering has come a long way. From ancient aquifers to locating natural gas deposits via satellite, the oldest branch of engineering in the world has literally left the planet. One technology that empowers modern civil engineers is geographic information systems GIS.

GIS enables engineers to capture and analyze spatial data. The data can then be presented in layered visualizations using digital geographic maps. GIS in civil engineering is providing valuable insights that were unprecedented. A significant sector of this market is devoted to engineering. The explosive growth of GIS technology means powerful new tools for engineers and scientists and exciting opportunities for investors and stakeholders. GIS is transforming, disrupting, and expanding the ways engineers serve society.

It provides layers of data on top of geographic maps that can help engineers and others make better-informed decisions. Imagine, if you will, a simple 2D map of a city. Now imagine selecting layers of data that can overlay the base map, and provide geographically significant information. The layers may represent rush hour traffic flow, underground water tables, or population density at 7 a. You can turn on as many layers as you want to get the information you need.

Oh, and those water tables? You can see them in 3D. And if you want to see the traffic density every hour on the hour, GIS can easily provide a dynamic view that shows traffic changes throughout the day. Microwave Remote sensing 5. Remote sensing Platforms and sensors 6. Visual Images Interpretation 7.

Digital Images Processing 8. Global positioning system GPS 9. Fundamentals of GIS Spatial data Modeling GIS data Management Data input and editing Data quality issues Data analysis and modeling Integration of remote sensing and GIS Urban and municipal Applications Forest resources management Watershed management Though broad categories are ofremote sensing is not limited to 10 or 15, or even cases, some described in Chapter It is Remote sensing has several unique advantages as.

This is very important a energy reflected from or natural source of energy, e. This sensing devices are often programmed to CRemote bias introduced in some in situ data collection can remove the sampling systematic investigations.

Synoptic view of a sensor is Remote sensing sensor. This ability area in comparison to the over a large geographic time and thereby cost dramatically traditional surveying methods.

This can help in monitoring data about areas that are physically and or Remote can be used for collecting sensing politically inaccessible. In this sense, it is much like surveying, providing moisture content, unlike investigations. Remote sensing is also different from the other mapping scicnces such as cartography or GIS because they rely on data produced clsewhere. Remote sensing science yields fiundamental scientific information. For example, a properly calibrated thermal infrared remote sensing system can provide a gcometrically correct map of land or sea-surface temperature without any other intervening scicnce.

A good example is the digital elevation modcls that are so important in nmany spatially distributed GIS models. Digital elevation modcls are now produccd almost exclusively through the analysis of remotely sensed data' Jenscn It is not a panacea that will provide all the information needed for conducting physical, biological, social science. It or simply provides some spatial, spectral, and temporal information.

Human beings select the most appropriate sensor to collect the data, specify the resolution of the data, calibrate the sensor, select the platform that will carry the sensor, determine when the data will be collected, and specify how the data are processed. Thus, human method-produced error may be introduced, as the various remote sensing instrument and mission parameters are specified Jensen Powerful active remote sensor system, such as lasers or radars that emit their own EMR, can be intrusive and affect the phenomenon being investigated.

Remote sensing instruments often become uncalibrated, resulting in uncalibrated remote sensing data. Finally, remote sensor data may be expensive to collect, interpret, or analyse. But, the information derived from the remote sensor data is so valuable that the expense is warranted. In doing so, we can then appreciate some of the problems encountered in the design and application of the various real remote sensing systems examined in subsequent chapters.

The basic components of an ideal remote sensing system include the following components Lillesand and Kiefer : A uniform energy source This source will provide energy all over wavelengths, at a constant, known, high level of output, irrespective of time and place.

Again, ideally this will hold irrespective of wavelength, timne. A super sensor This will be a sensor, highly sensitive to all wavelengths. This processing particular terrain element Because of the consistent nature information.

The derived state of each feature of interest. Descriptive Questions understand by r e m o t e sensing? What do you process.

Briefly explain EMR. What is electromagnetic content of a photon. Explain wave model frequency, and the wavelength, relation amongst with the atmosphere. Derive the incident EM energy i n t e r a c t i o n s of various 5. Explain with the target.

Explain absorptance, remote sensing' utilities in 7. Explain hemispherical what are its c u r v e and data. Explain understand analysis and by sensing? What do you and limitations of remote advantages a r e the I1. Open navigation menu. Close suggestions Search Search. User Settings.