Definition: A Geographic Information System (GIS), also known as a geographical information system or geospatial information system, is any system for capturing, storing, analyzing, managing and presenting data and associated attributes which are spatially referenced to Earth. [ Wikipaedia ]
Data is the fundamental component of any GIS and the power of a GIS is determined by its ability to relate different data in a spatial context and to reach a conclusion about this relationship. A combination of two data types: spatial (location data) and attributes (descriptive data) are related and presented visually by means of an interactive user interface, GIS software, using rastor and vector graphics.
Sources of data are vast (i.e. weather bureaus, NASA, municipalities, etc.) and the combination of sources often leads to more revealing and descriptive data analysis via spatial modelling and statistical methods. Given the availability of GIS components and that 80% of data can be geographically referenced, building your own GIS represents an increasingly viable and useful Management Information System (MIS) across manyapplications.
Components of GIS: