Change detection
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This document discusses using web-based GIS tools for change detection from satellite imagery before and after floods. It provides an introduction to GIS, describing it as a system for capturing, storing, analyzing and displaying spatially referenced data about the Earth. It also describes the key components of a GIS system, including spatial data input and storage in either vector or raster data models, as well as GIS software for transformation, analysis and output. Finally, it defines change detection as highlighting differences in imagery over time to update features based on new information.
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Change detection
- 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
- 3. GIS System Architecture and Components Data Input Query Input Geographic Database Output: Display and Reporting Transformation and Analysis
- 4. GIS components Specific applications / decision making objectives ? G I S Spatial data Computer hardware / software tools
- 8. Vector data Land use parcels
- 9. Raster data
- 14. GRIET 2003
- 15. GRIET 2005
- 16. GRIET 2007
- 17. GRIET 2007
- 18. GRIET 2008
- 19. GRIET 2010
Editor's Notes
- 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?