Change detection

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change detection of gis and if want to know more infromation mail me at maoj.rayudu@gmail.com

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  • 14
  • GIS components The key to establishing this type of technology within an information framework for the purposes of decision making is INTEGRATION: the linking together of technology, data and a decision making strategy. What GIS is all about today is the bringing together of spatial analysis techniques and digital spatial data combined with computer technology. But for many, GIS is much more than a computer database and a set of tools: it is also a philosophy for information management. Often GIS can form the core of the information management within an organisation. There are of course other definitions too. GIS is sometimes referred to as the tool whilst the user may be the Spatial Information Scientist! In recent times the whole subject area has also been referred to as Geographic Information Management (GIM) or even Geomatics Each of these components will now be examined in further details. 1. Data 2. Software & hardware tools 3. GIS data manipulation & analysis
  • Spatial data storage It is easy for us to recognise by eye the shape and form of objects or features such as those you have just examined (Burrough 1998). Computers require much more information and precision and, in fact, instructions on how to store such information. Spatial features or entities and their attributes are stored in computers using a number of spatial data models . It is important to understand the characteristics of them since the data model employed has considerable influence on the functionality of the GIS. The basic approaches are : • The Raster model • The Vector model The Raster data model is the simpler of the two and is based on the division of reality into a regular grid of identically shaped cells. The Vector data model is similar in its operation to the ‘join the dot’ books we all used as children. An object’s shape is represented by dots which are located where the shape of the object changes. The dots are joined by straight lines. In the vector data model the dots are known as vertices
  • Vector data This slide shows a typical example of some Vector data. It represents land use parcels from an American dataset. Notice how it is possible to colour code different types of land use. Question Can you think how this is possible? Jot down your ideas.
  • Raster Data This slide shows a typical example of some raster data. It represents an aerial photo/satellite image? Of a river valley. Question What do you think the different colours represent here?
  • Change detection

    1. 1. WEB BASED GIS TOOLS FOR CHANGE DETECTION USING SATELLITE IMAGERY DURING PRE AND POST FLOOD SCENERIES EXTERNAL GUIDE DR.T.V. RAJINIKANTH Presented by R.Manoj Kumar
    2. 2. INTRODUCTION <ul><li>What is GIS ? </li></ul><ul><li>“ A system for capturing, storing, checking, integrating, manipulating, analysing and displaying data which are spatially referenced to the Earth. This is normally considered to involve a spatially referenced computer database and appropriate applications software </li></ul>
    3. 3. GIS System Architecture and Components Data Input Query Input Geographic Database Output: Display and Reporting Transformation and Analysis
    4. 4. GIS components Specific applications / decision making objectives ? G I S Spatial data Computer hardware / software tools
    5. 5. Spatial data storage <ul><li>Vector model </li></ul><ul><li>Raster model </li></ul>as geometric objects: points, lines, polygons as image files composed of grid-cells (pixels)
    6. 6. Vector data model <ul><li>advantage of the vector data format: allows precise representation of points, boundaries, and linear features. </li></ul><ul><ul><li>useful for analysis tasks that require accurate positioning, </li></ul></ul><ul><ul><li>for defining spatial relationship (ie the connectivity and adjacency) between coverage features (topology), important for such purposes as network analysis (for example to find an optimal path between two nodes in a complex transport network) </li></ul></ul><ul><li>main disadvantage of vector data is that the boundaries of the resulting map polygons are discrete (enclosed by well-defined boundary lines), whereas in reality the map polygons may represent continuous gradation or gradual change, as in soil maps. </li></ul>
    7. 7. Raster data model <ul><li>good for representing indistinct boundaries </li></ul><ul><ul><li>thematic information on soil types, soil moisture, vegetation, ground temperatures </li></ul></ul><ul><li>as reconnaissance satellites and aerial surveys use raster-based scanners, the information (ie scanned images) can be directly incorporated into GIS </li></ul><ul><li>the higher the grid resolution, the larger the data file is going to be </li></ul>
    8. 8. Vector data Land use parcels
    9. 9. Raster data
    10. 10. Change Detection <ul><li>What is change detection ? </li></ul><ul><li>Change detection is used to highlight or identify significant differences in imagery acquired at different times; playing an important role in the lifecycle of GIS features and providing the capability to update feature data based on new imagery. </li></ul>
    11. 11. Land Cover Map <ul><li>Urban </li></ul><ul><li>Vegetation </li></ul><ul><li>Transportation </li></ul><ul><li>Utilities </li></ul><ul><li>Water Bodies </li></ul><ul><li>Wetlands </li></ul><ul><li>Barren Land </li></ul><ul><li>Vacant Land </li></ul>
    12. 12. Land Use Map <ul><li>Urban </li></ul><ul><ul><li>-Residential </li></ul></ul><ul><ul><li>-Industrial </li></ul></ul><ul><ul><li>-Commercial </li></ul></ul><ul><ul><li>-Services </li></ul></ul><ul><ul><li>-Cemetery </li></ul></ul><ul><ul><li>-Religions </li></ul></ul><ul><ul><li>Transportation </li></ul></ul><ul><ul><li>-Roads </li></ul></ul><ul><ul><li>-Bridges & Tunnels </li></ul></ul><ul><ul><li>-Railways </li></ul></ul><ul><ul><li>Utilities </li></ul></ul><ul><ul><li>-Power Lines </li></ul></ul><ul><ul><li>-Petroleum & Gas </li></ul></ul>
    13. 13. Land Cover Map <ul><ul><li>Vegetation </li></ul></ul><ul><ul><li>-Agriculture </li></ul></ul><ul><ul><li>-Natural Vegetation </li></ul></ul><ul><ul><li>Water </li></ul></ul><ul><ul><li>-Fresh Water Bodies </li></ul></ul><ul><ul><li>-Saline Water Bodies </li></ul></ul><ul><ul><li>Wetlands </li></ul></ul><ul><ul><li>Barren Land </li></ul></ul><ul><ul><li>Vacant Land </li></ul></ul>
    14. 14. GRIET 2003
    15. 15. GRIET 2005
    16. 16. GRIET 2007
    17. 17. GRIET 2007
    18. 18. GRIET 2008
    19. 19. GRIET 2010

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