The sigma -tree-a symbolic spatial data model

Spatial data models, in two and three dimensions, are especially important means for logical descriptions of images. Such models are necessary for both spatial reasoning and iconic indexing. A three dimensional hierarchical spatial data model designed for spatial reasoning is described in this paper. The model is built up from various types of building blocks of which the clusters are the most general. A significant feature is different views of the model which are means to support the reasoning process. Another feature supported by the model is the generation of 2D projections from the 3D structure. Methods for spatial reasoning by means of the model are discussed.<>