1 RS Chapter-1 introduction of RemS.pptx

Remote Sensing chapter one

1. Remote Sensing(RS) 1 Lecturer @ SNU : Abdirizak Abdullahi (Geyre) Lecturer @ SNU : Abdirizak Abdullahi (Geyre) Somali National University (SNU)

2. Chapter 1. Content INTRODUCTION Definition of remote sensing Remote sensing platforms History of remote sensing Elements of remote sensing process Applications of remote sensing Advantages of remote sensing Limitations of remote sensing

3. What is remote sensing and GIS course? Remote sensing is a surveying and data collection technique, regarding an object while GIS is a computer system that consists of software used to analyze the collected data and hardware that the software would operate in.

4. What is the meaning of remote sensing ? Remote – away from or at a distance Sensing – detecting a property or characteristic

5. This photograph is captured by normal camera and normally we call them image. You can see this is another image generated from a normal camera or may be DSLR. What is an Image ? INTRODUCTION

6. Here another image and its coverage is more and generally this kind of photographs are captured using some airborne sensors Here you can see also another image produced by a satellite.

7. basically image is a pictorial representation of an object or a scene. There are two forms of an images, Analog, and Digital.

8. What is remote sensing ? Definition Remote sensing is "the science and art of obtaining information about an object, area, or phenomenon through the analysis of data acquired by a device not in contact with the object, area, or phenomenon in question". The object is located on or near the earth surface and the sensor is more or less above the object. The information is carried by electromagnetic radiation.

9. Definition of remote sensing Remote Sensing can also be defined as “ The art, science and technology of obtaining reliable information about physical objects and the environment, through the process of recording, measuring and interpreting imagery and digital representations of energy patterns derived from non-contact sensor systems.” This is done by sensing and recording reflected or emitted energy and processing, analyzing, and applying that information."

10. Remote Sensing Platforms Remote sensing uses a sensor to capture an image Ground level remote sensing Very close to the ground (e.g., Hand held camera) Used to develop and calibrate sensors for different features on the Earth’s surface Aerial remote sensing Low altitude aerial remote sensing High altitude aerial remote sensing Space-borne remote sensing Space shuttles Polar orbiting satellites Geo-stationary satellites 10

11. Brief History of Remote Sensing 1839, the first photographs. 1849, used photography in topographic mapping. 1858, balloons were being used to acquire photography of large areas. 1925-1945 Mid 1930s, color photography. Aerial photography became widespread during World War II, with improved lenses and platform stability, enemy positions and military installations could be identified from aircraft. Radar

12. 1945-1960 Cameras were launched on rockets as this science expanded in the post-World War II era.   In 1957, the Russians launched the first successful Earth satellite, Sputnik 1 In 1958, the US launched its first satellite, Explorer 1. In 1959, the first satellite with a meteorological instrument (Vanguard 2) was launched. In 1960, the first satellite images ever made of the earth comes from the TIROS 1

13. 1960-1972 This was the age of instrument development. In 1964, the Nimbus satellite series of experimental meteorological remote sensing was initiated. By 1966, meteorological satellites moved from being experimental to being operational with the introduction of the ESSA series of satellites which included Automatic Picture. The Defense Meteorological Satellite Program (DMSP) was started by the U.S. Air Force in 1966. 1972, Landsat 1 (also referred to as Earth Resources Technology Satellite.

14. 1972-present 1975: The Synchronous Meteorological Satellites. 1976: Laser Geodynamic Satellite I. 1978: The Heat Capacity Mapping Mission. 1978: Sea sat demonstrated techniques for global monitoring of the Earth's oceans. 1978: Nimbus 7, the final satellite in that series, was launched. 1984: The Earth Radiation Budget (ERBE) satellite began its study of how the Earth absorbs and reflects the Sun's energy. 1991: The Upper Atmosphere Research Satellite (UARS) began its study of the chemistry and physics of the Earth's atmosphere. Today, the GOES (Geostationary Operational Environmental Satellite) system of satellites provides most of the remotely sensed weather information for North America.

15. The element of the remote sensing process Energy Source or Illumination Radiation and the Atmosphere Interaction with the Target Recording of Energy by the Sensor Transmission, Reception, and Processing Interpretation and Analysis Application

16. This diagram for remote sensing Orbit platform Radiation, EM specturm

17. 1.2 Elements of remote sensing process There are seven elements comprise the remote sensing process from beginning to end. 1. Energy Source or Illumination (A) - the first requirement for remote sensing is to have an energy source which illuminates or provides electromagnetic energy to the target of interest . 2. Radiation and the Atmosphere (B) – as the energy travels from its source to the target, it will come in contact with and interact with the atmosphere it passes through. 3. Interaction with the Target (C) - once the energy makes its way to the target through the atmosphere, it interacts with the target depending on the properties of both the target and the radiation. 4. Recording of Energy by the Sensor (D) - after the energy has been scattered by, or emitted from the target, we require a sensor (remote - not in contact with the target) to collect and record the electromagnetic radiation. 17

18. 5. Transmission, Reception, and Processing (E) - the energy recorded by the sensor has to be transmitted, often in electronic form, to a receiving and processing station where the data are processed into an image (hardcopy and/or digital). 7. Application (G) - the final element of the remote sensing process is achieved when we apply the information we have been able to extract from the imagery about the target in order to better understand it, reveal some new information, or assist in solving a particular problem. 6. Interpretation and Analysis (F) - the processed image is interpreted, visually and/or digitally or electronically, to extract information about the target which was illuminated. 18

19. 1.2. Applications of Remote Sensing Remote sensing has enabled mapping, studying, monitoring and management of various resources like agriculture, forestry, geology, water, ocean etc. It has further enabled monitoring of environment and thereby helping in conservation. In the last four decades it has grown as a major tool for collecting information on almost every aspect on the earth. With the availability of very high spatial resolution satellites in the recent years, the applications have multiplied. 19

20. Current major applications of remote sensing may as following: Geology Forestry Change detection Oceanography Meteorology Land degradation  Land use applications 20

21. Geology In geology, for instance, remote sensing can be applied to analyze and map large, remote areas. Remote sensing interpretation also makes it easy for geologists in this case to identify an area's rock types, geomorphology, and changes from natural events such as a flood or landslide. 21

22. 22 Landslide Hazards

23. Marine Applications. 1- Coastal Ecosystem Management Based on remote sensing, a variety of data pertaining to the coastal zone, like identification of plant community, biomass estimation, shoreline changes, delineation of coastal landforms and tidal boundary, qualitative estimation of suspended sediment concentration, chlorophyll mapping, bathymetry of shallow waters, etc. can be collected and all these data will help in effective coastal ecosystem management.

24. 2- Oil Spill Verification: A satellite image of the area where oil spill occurred contains suspended substances, such as hydrocarbons, sediment, foam or dye. In a remote sensing domain, these can be identified and measured in advance to curb and make effective assessment. Oil spill detection can be done by RADAR and thermal imagine. Eg. Miros OSD can operate in nearly all visibility conditions on a 24-hour basis, and has become an essential tool for navigating the recovery vessel and boom efficiently towards the oil slick (Fig.).

25. An early photo taken in 1973 from the NASA Skylab space station. It shows a thick layer of smog in the Los Angeles Basin (circled). Photo credit: NASA. Coastal applications: Monitor shoreline changes, track sediment transport, and map coastal features. Data can be used for coastal mapping and erosion prevention.

26. 3- Oceanography Remote sensing is applied to oceanography studies. Remote sensing is used, for example, to measure sea surface temperature and to monitor marine habitats . 26 Oceanography covers a wide range of topics, including marine life and ecosystems, ocean circulation, plate tectonics and the geology of the seafloor, and the chemical and physical properties of the ocean

27. Meteorology Remote sensing is an effective method for mapping cloud type and extent, and cloud top temperature. 27

28. Forestry 28 Satellite imagery is used to identify and map: - • The species of native and exotic forest trees. • The effects of major diseases or adverse change in environmental conditions. • The geographic extent of forests. etc

29. Satellite imagery is not always able to provide exact details about the species or age of vegetation. However, the imagery provides a very good means of measuring significant change in vegetation cover, whether it is through clearing, wildfire damage or environmental stress. The most common form of environmental stress is water deficiency. Change detection 29

30. Land degradation Imagery can be used to map areas of poor or no vegetation cover. A range of factors, including saline or sodic soils, and overgrazing, can cause degraded landscapes. 30

31.   land use applications Additionally, those studying urban and other land use applications are also concerned with remote sensing because it allows them to easily pick out which land uses are present in an area. This can then be used as data in city planning applications and the study of species habitat, for example. 31

32. Advantages of Remote Sensing Major advantages of remote sensing are Provides data for large areas Provide data of very remote and inaccessible regions Able to obtain imagery of any area over a continuous period of time Possible to monitor any anthropogenic or natural changes in the landscape Relatively inexpensive when compared to employing a team of surveyors Easy and rapid collection of data Rapid production of maps for interpretation

33. Limitations of Remote Sensing Some of the drawbacks of remote sensing are The interpretation of imagery requires a certain skill level Needs cross verification with ground (field) survey data Data from multiple sources may create confusion Objects can be misclassified or confused Distortions may occur in an image due to the relative motion of sensor and source

34. Thanks