A Hierarchical 3D Spatial Model Based on User-Defined Data Types

Based on user-defined data types, a novel 3D data model is proposed in this paper. The spatial data model is a hierarchical structure consisting of Objects, Sub-objects, and Geometries. Objects are composed of Sub-objects, which in turn are made up of Geometries. The relationship between an object and its sub-objects is many to many in the data model. A geometry object can be represented by three different types: discrete object, function and object reference. We first describe spatial data types using generic terminology without referring to any specific solution. And then discuss how to structure spatial data into tables and define the right table structure. As the rules of geometry object construction do not concentrate on triangles or planar polygons, this model is able to handle complex objects which are an essential functionality for building large-scale cyber cities.