gis

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global information system

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well made for beginners

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how can i download tis.. a nice ppt

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if u want this, I can mail u. - atul

 
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Presentation Transcript

Slide 1: 

BY – ATUL TEMBE

Geographic Information System (GIS) is a computer based information system used to digitally represent and analyze the geographic features present on the Earth' surface and the events that taking place on it. Anything that can appear on a map can be encoded into a computer and then compared to anything on any other map, using longitude-latitude coordinates. GIS is essentially a marriage between computerized mapping and data base management systems. : 

Geographic Information System (GIS) is a computer based information system used to digitally represent and analyze the geographic features present on the Earth' surface and the events that taking place on it. Anything that can appear on a map can be encoded into a computer and then compared to anything on any other map, using longitude-latitude coordinates. GIS is essentially a marriage between computerized mapping and data base management systems. Understanding GIS

What GIS Does ? : 

What GIS Does ? Mapping and *cartography: Visualize features and manipulate *symbology and colours to create an output map with title, scale bar, north arrow etc. Query: Ask questions of feature attributes such as: where is…? What’s the nearest…? What intersects with…? Select: Identify features and their attributes that meet some criteria. Distance: Calculates the distance between features. Buffers: Rings drawn around features at a specified distance from the features. Continued…. *Cartography - the production of maps, including construction of projections, design, compilation, drafting, and reproduction. *Symbology – study of symbols

What GIS Does ? : 

What GIS Does ? Overlay: The display of multiple layers of information at one location. Clip: Cuts an input layer to the size and extent of a selected layer. Merge: Combines multiple layers into one layer. *Raster analysis: There is a whole separate suite of tool for raster analysis that includes classifying cells, deriving aspect and slope, *mosaicking and calculating new cell values among many others. 3D: Data can be viewed with ‘height’ in 3-dimensions for powerful visualization. *A raster data type is, in essence, any type of digital image/ Representation as a regular grid of cells *mosaicking - a picture or decoration made of small, usually colored pieces of inlaid stone, glass, etc.

Slide 5: 

Creating GIS Essentially, geographic information states what is where. So to create geographic information, we have to record these two elements somehow. They can be captured through many different types of observations, measurements and surveys. Data can be sourced from aerial photography, satellite images, field samples, land surveying, population censuses, global positioning systems (GPS) and government administrative records among others.

How To Combine Geographic Information? : 

How To Combine Geographic Information? If we are combining a number of different geographic information themes together, they may be from different sources, in different formats and covering different study areas. Therefore, we need to use a system to deal with the *disparate sources and organize them so that they can be combined. A Geographic Information System does just that. It is a tool for the input of different geographical information themes so that they can be stored, organized, displayed and analyzed. It uses geography as the common denominator between separate themes so that they can be combined. Its purpose is to provide answers to questions based on geographical data *Disparate - distinct in kind; essentially different; dissimilar

Slide 7: 

Relating info. from different sources Data capture Data integration Projection and registration Data structures Data modeling Techniques used in GIS

GIS : Analysis Tool in Real Estate : 

GIS : Analysis Tool in Real Estate A GIS does in fact create high quality maps that communicate considerable amounts of information in an efficient and attention-getting manner. ("A picture is worth a thousand words.") For example, when used to select the best site for a major retail store in a certain city or region, in a few seconds a GIS can simultaneously display on the computer monitor: All the census tracts (region wise market research data) in the city, with the color of each tract (area) reflecting the number of households and median household income Major locations with traffic volumes listed next to each street segment The sites of all potential competitors, shown as dots, with the size of each dot drawn proportional to the square footage or gross sales of that competitor The locations of any toxic waste sites, flood zones, earthquake faults, or other environmental constraints

Advantages GIS : 

Advantages GIS Can cope with larger amounts of data Can cover large study areas (the whole world if necessary) Can cope with unlimited and frequent edits and changes More robust and resistant to damage Faster and more efficient Requires less person time and money

Slide 10: 

Glossary of Terms Glossary of terms

Data Capture : 

Data Capture Putting the information into the system—involves identifying the objects on the map, their absolute location on the Earth's surface, and their spatial relationships. Software tools that automatically extract features from satellite images or aerial photographs are gradually replacing what has traditionally been a time-consuming capture process. Objects are identified in a series of attribute tables—the "information" part of a GIS. Spatial relationships, such as whether features intersect or whether they are adjacent, are the key to all GIS-based analysis. HOME

Data Integration : 

Data Integration A GIS makes it possible to link, or integrate, information that is difficult to associate through any other means. Thus, a GIS can use combinations of mapped variables to build and analyze new variables HOME

Projection & Registration : 

Projection & Registration A property ownership map might be at a different scale than a soils map. Map information in a GIS must be manipulated so that it registers, or fits, with information gathered from other maps. Before the digital data can be analyzed, they may have to undergo other manipulations—projection conversions, for example—that integrate them into a GIS. Projection is a fundamental component of mapmaking. A projection is a mathematical means of transferring information from the Earth's three-dimensional, curved surface to a two-dimensional medium—paper or a computer screen. Different projections are used for different types of maps because each projection is particularly appropriate for certain uses. For example, a projection that accurately represents the shapes of the continents will distort their relative sizes. Since much of the information in a GIS comes from existing maps, a GIS uses the processing power of the computer to transform digital information, gathered from sources with different projections, to a common projection HOME

Slide 14: 

An elevation image classified from a satellite image of Minnesota exists in a different scale and projection than the lines on the digital file of the State and province boundaries. The elevation image has been re-projected to match the projection and scale of the State and province boundaries HOME

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