BA-GeographyandDevelopment-4-Dr.RichaChaturvedi-IntroductiontoRemoteSensingandGIS-Unit4.ppt
- 1. INTRODUCTION TO REMOTE SENSING & GEOGRAPHICAL INFORMATION SYSTEM
- 2. In the world of geospatial science, Remote Sensing also know as the earth observation. Remote Sensing is made from two words Remote and Sensing. ‘Remote’ means far away and ‘sensing’ means acquiring some information. National Remote Sensing Agency (NRSA): Remote sensing is the technique of deriving information about objects on the surface of the earth without physically coming into connect with them. Canada Centre for Remote Sensing (CCRS): 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.
- 3. REMOTE SENSING PROCESS Radiation by energy source: the first requirement for remote sensing is to have an energy sources that illuminates or radiates electromagnetic energy to the target of interest. Sun is the natural sources of energy and it is in the form of EMR. Interaction of energy with atmosphere: As the energy travels from its sources to the target, it will come in contact with and interact with atmosphere it passes through. When the energy sources is the sun, then first of all the energy comes through vacuum where no interaction happens before interacting with the earth’s atmosphere. Interaction of energy with the target: 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. Some amount of incident energy is then reflected or emitted from the target.
- 4. Interaction of energy with atmosphere: As the reflected or emitted energy travels from its target to the sensing or imaging device, it interacts with the atmosphere once again. Recording of energy by sensor: After the energy has been reflected by or emitted from the target we require a sensor to collect and record the EMR. Transmission, reception and processing: The energy recorded by the sensor has to be transmitted, often in electronic form, to a receiving and processing station on the ground where the data are processed into an image. Interpretation and Analysis: The processed image is interpreted, visually or electronically, to extract information about the target of interest. Application: Finally we apply the information we have been able to extract from the imagery about the target to better understand it, reveal some new information or assist in solving a particular problem.
- 5. REMOTE SENSING PLATFORMS: The base, stationary or moving on which remote sensors are mounted is called a platform. Three types of platforms are existing in remote sensing process. 1.Ground base platform- Tripod stand etc. 2.Atmosphere base platform- balloons, helicopter, aero plane etc. 3. Space –based platform- rocket, satellite
- 6. 1. High resolution of data recorded. 2. Possibility of carrying large payloads. 3. Capable of imaging large area economically. 4. Accessibility of remote area. 5. Convenience of selecting different scales. 6. Adequate control at all time. The advantages of using aircrafts as remote sensing platform are –
- 7. The geographical information system consists of two distinct disciplines namely, Geography and Information System. Geography + Information System Geography is the science which involves a combination of physical and cultural disciplines, which are used to describe, explain and help us to understand our environment and our relationship with it. Information System can be defined as an interactive combination of people, computer hardware and software, communications device and procedures designed to provide a continuous flow of information to the people who need information to make decision or perform analysis.
- 8. A Geographical Information System (GIS) is a system of hardware, software and procedures to facilitate the management, manipulation, analysis, modeling, representation and display of geo referenced data to solve complex problems regarding planning and management of resources. Arnoff: A computer based system that provides four sets of capabilities to handle geo referenced data: data input, data management, manipulation and analysis and data output. Peter Burrough: GIS is a powerful set of tool for collecting, storing, receiving at will, transforming and displaying spatial data from the real world for a particular set of purpose.
- 10. GIS- THREE VIEW OF INFORMATION SYSTEM DATA BASE OR TABLE VIEW: GIS is a unique kind of data base of the world a geographic database. It is based on structural database that describes the world in geographic term. MAP VIEW: GIS is a set of intelligent maps and other views that show features and feature relationship on the earth surface. Maps of the underlying geographic information can be constructed and used to support queries, analysis and editing of the information. MODEL VIEW: A GIS is a set of information tools that derive new geographic database from existing database. By combing data and applying some analytic rules, we can create a model that helps answer the question we have posed.
- 11. FUNCTIONS OF GIS DATA CAPTURE: Data capture is the operation of encoding data for inclusion into a digital database. Various technique can capture the information. Map can be digitized, or hand traced with a computer mouse to collect the coordinates of features. Electronic scanning device will also convert map features into digital format. DATA SOURCE: the first requirement for source data involves knowledge of the locations for the variables. The data sources for GIS are: Conventional analog map source Reports and Publication Aerial remote sensing Satellite imagery Field data source Existing digital map sources
- 12. DATA INTEGRATON: A GIS makes it possible to link or integrate information that is difficult to associate through any other means. Once we join both type of data (spatial and attribute data) using any GIS software , our GIS is now ready for use. ORGANIZAING DATA FOR ANALYSIS: The main uses of GIS are data analysis and presentation of spatial data. Most GIS software organize spatial data in a thematic approach that categorize data in vertical layers.
- 13. TECHNICAL AND CONCEPTUAL DEVELOPMENT OF GIS THROUGH TIME Cartography (Including High Quality Drafting) Computer added design & Computer Graphics Surveying and Photogram try Spatial Analysis Interpolation from Point Data Remote Sensing Technology TIME GIS
- 14. LIMITATION OF GIS GIS has a many beneficial applications, however like other technological systems, there are also some limitations to its use. GIS Data are more expensive than traditional data. GIS integrates several individual subjects, which demands proper knowledge on all of integrated subject. GIS needs specialized computer equipment and software. Privacy and security issues can sometimes limit distribution of data. Learning time on GIS software and system can be long. Data development and maintenance is the most costly and labour intensive work in GIS field
- 15. APPLICATION OF REMOTE SENSING & GIS •Natural recourse Management •Infrastructural Development •Utility Services •Hydrology •Geology •Land Use Planning •Urban Planning •Disaster management and Mitigation •Forest cover Mapping