GIS is a computer-based tool that facilitates mapping and spatial analysis of Earth's features and events. Using GIS, otherwise disparate data can be related on the basis of common geographic location, creating new information from existing data resources. Hidden in most data is a geographical component: an address, postal code, census block, city, county, or latitude/longitude coordinate. GIS software lets you see, explore, and analyze data by location, revealing hidden patterns, relationships, and trends that are not readily apparent in spreadsheets or statistical packages.
             With GIS, you can display soil types, track crime patterns, analyze animal migration patterns, find the best location for an expanding business, model the path of atmospheric pollution, and much more. You don't use a GIS simply to make static maps, although you can produce beautiful maps with it. It is a dynamic system that allows you to select and remove any criteria on the map to quickly analyze how different factors affect your model and ultimately makes decisions for complicated problems.
             GIS stands for Geographic Information Systems. GIS is sometimes referred to as computer mapping, but it is really much more powerful than that. GIS organizes information normally seen on a single map into layers or themes, such as roads, streams, buildings, contour lines, etc. These themes can be turned off and on with a click of a button to communicate different information to the user. Associated with each theme is a database table that lists attributes for each individual feature in the theme. If, for example, you have a building theme of a college campus, each building would have information stored in the database that might include its name, the number of stories, its area, its construction date, when it was last painted, and its primary function.
             Data Formats. Some types of data, such as the examples above, are best portrayed as points, lines
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