Construction of Convex Hull for Three Dimensional Data Model of Real Estate Unit

With the rapid growth of the utilization of urban land in multiple spatial dimensions in China, from the surface of land parcels to the space below or above them, it is an urgent demand for the vertical expression of land rights. Due to the traditional 2D cadastre can hardly represent these complex land right, some recent researches focus on so-called 3D cadastre or 3D real estate unit. In view of the critical issue that the current 3D spatial data models are difficult to describe irregular real estate unit, a method of convex hull of 3D spatial data model was proposed. We built first the convex hull of the whole 3D unit and its concave boundary, and then got the rid of their intersection parts to obtain its 3D vector volume. We also improved the algorithm of convex hull. Our experiments show that the method is suitable for automatic construction of irregular 3D real estate units. Moreover, it can be easier to the integration and transformation between the surface and volume models of the 3D spatial unit.