A Unified Building Model for a Real 3D Cadastral System

Abstract

Cadastral systems today are mostly based on digitally represented 2D parcel maps or land registries of 3D components referenced to different documents. With clear limitations to this method, this chapter focuses on creating 3D property information based on existing 3D building models. It starts by investigating shortages of the most prominent semantic building models for BIM and geospatial models (IFC and CityGML, respectively) as well as a pre-developed Unified Building Model (UBM). The result shows that neither one of the three has capabilities for complete 3D cadastre systems. The chapter proposes an extension to the UBM by adding four subtypes to the boundary surfaces above- and under-ground, namely “Building Elements,” “Digging,” “Protecting Area,” and “Real Estate Boundary.” The extended UBM is then implemented in a case study of a hospital building in Sweden and shown to be able to model all surfaces that define 3D cadastral information of buildings. The extended UBM is argued to contribute to e-planning in cities and urban applications as well as to 3D cadastral applications.