Geographic Information System(GIS)
Geographic Information System(GIS) is a computer system that records,stores and analyzes information about the features that make up the earth’s surface. A GIS can generate two or three dimensional images of an area,showing such natural features as hills and rivers with artificial features such as roads and power lines.Scientists use GIS images as models , making precise measurements, gathering data and testing ideas with the help of the computer.
Many GIS databases consist of sets of information called layers. Each layers represents a particular type of geographic data.A GIS database can include as many as 100 layers.
A GIS is designed to accept geographic data from a variety of sources ,including maps ,satellite photographs and printed text and statistics. GIS sensors can scan some of this data directly.The GIS converts all geographical data into a digital code,which it arranges in its database. Operators program the GIS to process the information and produce the images or information they need.
The applications of a GIS are vast and continue to grow.By using a GIS, scientists can research changes in the environment , engineers can design road systems ,electrical companies can manage their complex networks of power lines,governments can track the uses of land and fire and police departments can plan emergency routes.Many private businessess have begun to use a GIS to plan and improve their services.
The idea of using map layers is an old one. Layered information from traditional maps had been used for practical purposes for a long time. But computers made the application of this concept much more practical.
GIS was a welcome change from the era of hand cartography when maps had to be painstakingly created by hand ,even small changes required the creation of a new map . The earliest version of a GIS was known as computer cartography and involved simple line work to represent land features on the top of each other to determine patterns and causes of spatial phenomenon.
The capabilities of GIS are a far cry from the simple beginnings of computer cartography. at the simplest level ,GIS can be thought of as a high-tech equivalent of a map. However,not only can paper maps be produced far quicker and more efficiently,the storage of data in an easily accessible digital format enables complex analysis and modeling not previously possible. The reach of GIS expands into all disciplines and has been used for such widely ranged problems such as prioritizing sensitive species habitat to determining optimal real estate locations for new businesses.
The keyword to this technology is geography,this usually means that the data is spatial, in other words ,data that is in some way referenced to locations on the earth. Coupled with this is usually data known as attribute data. Attribute data generally defined as additional information, which can be tied to spatial data. An example of this would be schools. The location of the schools is the spatial data. Additional data such as the school’s name,level of education taught ,school capacity would make up the attribute data. It is the partnership of these two data that enables GIS to be such an effective problem solving tool.
GIS operates on many levels. On the most basic level , GIS is used as computer cartography , i.e. mapping. The real power in GIS is through using spatial and statistical methods to analyze attribute and geographic information. The end results of the analysis can br derivative information, interpolated information.
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