Geographic Information Systems
Dec 6, 2013
Dr R Jayashree Asst. Professor(AGB) Veterinary College,
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Definition • A GIS is a particular form of Information System applied to geographical data. In a GIS the common purpose is decision making to manage: land resources transportation retailing OR any other spatially distributed activity Dec 6, 2013
Dr R Jayashree Asst. Professor(AGB) Veterinary College,
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What is a Geographic Information System (GIS)? • A GIS is an organized collection of computer hardware, software, geographic data, and personnel to efficiently capture, store, update, manipulate, analyze, and display all forms of geographically referenced information. • A GIS integrates spatial and other kinds of information within a single system to provide a consistent framework for analyzing geographic (spatial) data. Dec 6, 2013
Dr R Jayashree Asst. Professor(AGB) Veterinary College,
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What is a Geographic Information System (GIS)? • A GIS makes connections between activities based on geographic proximity. • The digital data structure can be conceptualized as a set of “floating electronic maps” with a common registration allowing the used to “look” down (drill down) and across the stack of maps. • The spatial relationships can be summarized (data base inquiries) Dec 6, 2013
Dr R Jayashree Asst. Professor(AGB) Veterinary College,
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GIS - Map Stacking NDVI From Aerial Image Nitrogen Availability Estimate from Aerial Photo
pH Layer
Geographic Information System Dec 6, 2013
Courtesy of PPI
Normalized Difference Vegetation Dr R Jayashree Asst. Professor(AGB) Index (NDVI) Veterinary College,
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GIS Process Capture Data Register Map Base Interpret Data
Store Data in Computer
Convert Data to Digital Format
Process Data Display Results Dec 6, 2013
Dr R Jayashree Asst. Professor(AGB) Veterinary College,
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Images
Maps
Image Processing System Map Digitizing System
Geographic Analysis System
GIS System Dec 6, 2013
Spatial Attribute Data Data Base Base
Statistical Reports Statistical Analysis System
Database Management System
Cartographic Display System Maps
Dr R Jayashree Asst. Professor(AGB) Veterinary College,
Statistics Tabular Data
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• Livestock resources such as population, fodder, etc., of a nation, state or region shown in a map using colours for various species or types, makes it easy to spot where density of population is high and low. Policy makers/Researcher then has knowledge of where density is lower or higher than expected. Without a GIS this kind of analysis is so time consuming that it is not done on a regular basis. Problem areas will remain undiscovered, and actions will get delayed for months or even Dec 6, 2013 Dr R Jayashree Asst. Professor(AGB) years. Veterinary College,
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GIS Data Formats • There are two formats used by GIS systems to store and retrieve geographical data:
– Raster – Vector
Dec 6, 2013
Dr R Jayashree Asst. Professor(AGB) Veterinary College,
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Raster Format • • • •
Data are divided into cell, pixels, or elements Cells are organized in arrays Each cell has a single value Row and Column Numbers are used to identify the location of the cell within the array. Perhaps the most common example of raster data is a digital image.
Dec 6, 2013
Dr R Jayashree Asst. Professor(AGB) Veterinary College,
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Vector Format • Data are associated with points, lines, or boundaries enclosing areas • Points are located by coordinates • Lines are described by a series of connecting vectors (line segments described by the coordinates of the start of the vector, its direction, and magnitude or length). • Areas or polygons are described by a series of vectors enclosing the area. Dec 6, 2013
Dr R Jayashree Asst. Professor(AGB) Veterinary College,
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Vector and Raster Representation of Point Map Features Map Feature
GIS Vector Format (X,Y) Coordinate in space
Dec 6, 2013
Dr R Jayashree Asst. Professor(AGB) Veterinary College,
GIS Raster Format Cell Located in an Array
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Vector and Raster Representation of Line Map Features
Dec 6, 2013
Dr R Jayashree Asst. Professor(AGB) Veterinary College,
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Vector and Raster Representation of Area Map Features Map Feature
Dec 6, 2013
GIS Vector Format
Dr R Jayashree Asst. Professor(AGB) Veterinary College,
GIS Raster Format
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Solar GIS
Dec 6, 2013
Coastal area GIS
Dr R Jayashree Asst. Professor(AGB) Veterinary College,
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Epidemiology survey Africa
Dec 6, 2013
Dr R Jayashree Asst. Professor(AGB) Veterinary College,
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Dec 6, 2013
Dr R Jayashree Asst. Professor(AGB) Veterinary College,
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Dec 6, 2013
Dr R Jayashree Asst. Professor(AGB) Veterinary College,
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Dec 6, 2013
Dr R Jayashree Asst. Professor(AGB) Veterinary College,
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Thank You
Dec 6, 2013
Dr R Jayashree Asst. Professor(AGB) Veterinary College, Bangalore
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