Geo-Informational systems represent the possibility of computer analysis of the objects that exist on the earth and the events happening on it. GIS technologies concerning usual operations of data-bases, such as searching and statistical analysis, combine with such unique advantages of geographic map as visualization and so on.
These opportunities make GIS different from all other informational systems and make useful for a broad spectrum of private and public organizations. It can be used for explaining events, forecasting results and planning strategies.
Cartography and geographical analysis is not innovation, but GIS executes these tasks better and faster than other, manual methods.
Before GIS was created, there were a limited number of persons with essential abilities for making decisions and solving problems using geographic information.
Nowadays GIS is a multi milliard dollars industry, where thousands of people are employed from all over the world. GIS is taught in schools, colleges and universities.
The professionals in all fields realize that, thinking and acting with geographical approach is more advantageous.
Suppose we are looking for a place, where we want our office to be, the best ground for growing bananas, or optimal route for ambulance, for this we have to take into account the geographical components by all means. GIS gives you an opportunity you have never had before, such as: creating maps, integrating information, visualization of various scripts, solving complex problems, presentation of new ideas, looking for effective decisions.
GIS is used by individuals, as well as by organizations, schools, governments and enterprises, which need to find innovation ways for solving problems.
Working Principe of GIS
GIS stores the information about the world as the collection of thematic layers. Each layer can be connected to each other by geography. This simple but very multiform conception not once has proved that, it’s unchangeable for solving many real problems, like watching after the automobile movement, fixing planning details properly or modeling global atmospheric circulation.
Geographical Data
Any geographic information includes concrete geographic information. (ex.: latitude and longitude, or coordinate system) or more general indications, such as an address, postal index, name of description region, location of the forest or the name of the road.
Automatic process called geo-coding, gives an opportunity to create concrete geographic data (multiple locations) from general geographic data (addresses), which allows to ascertain locations of a business or forest stand, or even of events (such as an earthquake) on the earth's surface and then analyze the information we have got.
Vector and Raster Models
Geographic informational systems use two fundamentally different types of geographic models – the vector model and the raster model.
In the vector model, information about points, lines, and polygons is encoded and stored as a collection of X and Y coordinates. The location of a point feature, such as a bore hole, can be described by a single X and Y coordinates. Linear features, such as roads and rivers, can be stored as a collection of point coordinates. Polygonal features, such as realization territories, can be stored as a closed loop of coordinates.
The vector model is extremely useful for describing discrete features, but less useful for describing continuously varying features such as soil type or accessibility costs for hospitals. The raster model has evolved to model such continuous features. A raster image comprises a collection of grid cells rather like a scanned map or picture.
Both the vector and raster models for storing geographic data have unique advantages and disadvantages. Modern GIS-es are able to handle both models.
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