Geographic Information System
Geographic information system (GIS) provide a technology and method to analyze spatial data, or information about the Earth. The Earth’s climate, natural hazards, population, geology, vegetation, soils, land use, and other characteristics can be analyzed in a GIS using computerized maps, aerial photographs, satellite images, databases, and graphs. |
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| What are Geographic Information Systems? |
| Geographic Information Systems (GIS) may be described as an IT based system for collection, adaptation, analysis and presentation of geographical data. |
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| A brief historical survey |
| Geographical information system (GIS) is a young subject. GIS has its point of departure in traditional thematic cartography. The progress within cartography, photogrammetry and computer technology gave the foundation for development of the first GIS in Canada and the USA in the middle of the sixties. |
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| Why GIS? |
| There may be different reasons why an organisation starts using GIS. The most important reason may be to rationalise. Access to official databases for instance within environmental protection or road building may result in faster and more effective planning. |
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| GIS and certain definitions, clarifications of conceptions |
| A GIS system will, as previously mentioned, have functions for loading, adaptation, storing, analysis and presentation of geographical data. In an operational GIS one or more databases are included. |
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| The structure of GIS |
| In order to construct a GIS one has to go through several phases. All phases are necessary to arrive at a result. |
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| Data used in a GIS |
| Geographical data consist of two main components: geometry and attributes. The geometry describes points, lines and flats. To these geometrical objects, attributes of different types are linked. |
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| GIS and databases |
| There are many methods and techniques for storing and organising the structures in digital form. Electronic storing demands special organisation and structure of the data if they are to be quickly retrieved and linked. |
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| Data analysis in GIS |
| The GIS tool opens up for a possibility of connecting localized information, and transforming it, for instance, by using mathematical formulas. In addition to being a tool of outlaying and storing, GIS is also a tool of analysis. |
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| Data quality and sources of errors |
| Data quality and sources of errors in GIS have been mentioned in different connections. This is a question of balance between the need for quality and costs |
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| Data capture |
| Data capture is a method used for the collection of confirmed information. In order to understand the properties of confirmed data and their areas of application, one ought to know about methods of data capture. |
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