GIS: a GIS, or Geographical Information System, is a computer based system which analyses spatially referenced or geographical data for research and/or management purposes. A GIS is commonly envisaged as comprising computer hardware and software and georeferenced spatial data sets. However, it also encompasses appropriate procedures and techniques, and appropriately trained personnel. Key capabilities of GIS include: easy access to large volumes of (spatial) data; facilities for data searching, selection, analysis and modelling; and, output of maps and other formats tailored to meet particular needs.