•Two-dimensional (2D) is based on the Cartesian coordinate (x,y) system. 2D mapping is limited to representation of data on planar surfaces.
•Two and one half-dimensional (2.5D) is a common format used by most GISs. They are generally for modelling of surfaces or terrain through (x,y) and attribute values.
•Three-dimensional (3D) -The 2D point, line, and polygon vector representation of objects extends to include a volume element in 3D space. More efficient to handle holes orvoidswithin volumetric bodies (e.g. caves).
•Four-dimensional GIS (volumes over time) is important for showing processes that occur in nature and through time.