GEOGRAPHIC INFORMATION SYSTEM

A computer system for storage, analysis and retrieval of information, in which all data are spatially referenced by their geographic coordinates (north, east). In addition to primary data, such as climatic and soil characteristics, a GIS can be used to calculate derived values, such as erosion hazard, forest yield class, or land suitability for specified land-use types. Data are usually derived from maps and derived values can be printed out as maps. FAO (1993)