GIS work?

How It Works GIS GIS is used to store the world information that can be linked through geographical collection of all the theme layer. This simple but very powerful and versatile concept, for solving many real world of Wentijuyou invaluable in Zuoyong, these issues include: Genzongzhuanshu tool which records detailed information on programs, simulate global atmospheric Xunhuan 绛?



Geographic Reference System

Geographic information contains clear geographic reference system, such as longitude and latitude coordinates, or a national grid coordinates. Can also include indirect geographic reference system, such as address, zip code, census area names, forest location identification, road names and so on. Called geo-coding system for the automatic processing system from the indirect reference, such as the address description into a specific geographic reference system, such as multiple positioning. The geographic reference system allows you to locate a number of characteristics, such as business activity, forest location, you can also locate a number of events, such as earthquakes, for to do surface analysis.
Vector and raster mode
Geographic information systems work in two different basic geographic pattern - vector mode and grid mode. In the vector model, on the point, line and polygon information is encoded and to x, y coordinate of form. Position of a point feature, such as a drill, can be a single x, y coordinates described. Line features, such as roads and rivers, can be stored in a series of point coordinates. Polygon features, such as sales area or gathering area rivers, can be stored in a closed loop of coordinates. Vector model is very beneficial to describe the characteristics of a number of discrete, but continuous changes in the characteristics, such as soil type, or rushed to hospital costs, etc., will not be useful. Grid pattern development as a continuous feature of the model. Raster image contains a grid cell, a bit like a scanned map or photo. Either vector or raster mode model, used to store geographic data, there are advantages and disadvantages. Modern GIS can handle both modes.

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