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From zweieinhalbdimensional (short: 2 ½ D, 2 ½ D or 2.5D), it is called with data models, in which the third dimension to the non-respect fully satisfying 2D -Lageinformation is stored. Rather, the third dimension is only available as an attribute of the two-dimensionally modeled objects. The term is u. a. used in geographic information systems and the design of databases .

For example, with digital elevation models, the terrain height is usually modeled as a function of the location. There is only one height value in the model for each 2D position coordinate. Vertical walls, overhangs, cavities, tunnels and bridges cannot be integrated in such a model because in reality points of different heights are superimposed there. In order to express that despite the 3D model (position and height are modeled) not all 3D shapes can be modeled, the term 3D is weakened by using 2.5D.


  • Ralf Bill: Basics of geographic information systems. Volume 1. p. 12