A geographic information system (GIS) is a system designed to capture, store, manipulate, analyse, manage, and present all types of geographical data. The key word to this technology is geographical – this means that some portion of the data is spatial. In other words, data that is in some way referenced to locations on the earth.
Coupled with this data is usually tabular data known as attribute data. Attribute data can be generally defined as additional information about each of the spatial features. An example of this would be schools. The actual location of the schools is the spatial data. Additional data such as the school name, level of education taught, student capacity would make up the attribute data.
It is the partnership of these two data types that enables GIS to be such an effective problem solving tool through spatial analysis. GIS can be used as tool in both problem solving and decision making processes, as well as for visualisation of data in a spatial environment. Geospatial data can be analysed to determine:
the location of features and relationships to other features
where the most and/or least of some feature exists
the density of features in a given space
what is happening inside an area of interest (AOI)
what is happening nearby some feature or phenomenon
how a specific area has changed over time (and in what way).