Modelling the legal spaces of 3D underground objects in a 3D LAS

Abstract

Urbanisation and a lack of available construction land has led to the increased development of underground space which can contribute to the development of the urban areas by providing space for the construction of (infra)structural objects and networks necessary for a city to function and provide services to its citizens. The main challenge in developing the underground space is registering the RRRs of the underground objects into Land Administration Systems (LASs). Registering the RRRs of these underground objects in 3D can facilitate a better understanding, as well as a more efficient registration and clear visualisation of the RRRs.
To register the objects below the surface in a 3D LAS, 3D physical data as well as 3D legal data need to be registered and integrated into one model. BIM/IFC models can be (re)used as input data to register the 3D physical data. To register the 3D legal data in an efficient way, the ISO 19152:2012 Land Administration Domain Model (LADM) standard can be applied. The motivation for linking the BIM/IFC models with the LADM is that the geometry of the BIM/IFC models can be reused from design for the registration of the legal spaces in LASs or that BIM/IFC models can serve as a technical encoding for the exchange of data in LASs and thereby connect the workflows from the (AECOO) community. In this research the mapping of the basic classes of the LADM to IFC entities is presented to support the linkage of these two data models.
Research to investigate the implementation of the LADM in a 3D LAS, with the use of BIM/IFC models as input for 3D objects on the surface such as apartment buildings and infrastructure objects has been carried out. The result of this research was that the RRRs of objects on the surface can easily be determined by applying the legal information from the enriched BIM/IFC model. No research has been done in implementing the LADM in a 3D LAS, with the use of BIM/IFC models as input for 3D objects below the surface. This research will therefore complement the earlier related work, thereby supporting the modelling of legal information of all 3D objects, below as well as on the surface.
To solve the challenges that currently prevent the implementation of 3D objects below the surface in LASs and to harmonise the different (technical and semantic) requirements for LASs a standardised workflow was developed and is presented in this thesis. The standardised workflow shall provide more insight into the modelling of the legal spaces of 3D objects below the surface, stimulate the exchange of data across the AECOO community, and promote the use and development of 3D LASs.
Two case studies were conducted, where objects (pipes) from the sewage system and a tunnel were used. The tunnel was a BIM/IFC model, while the sewage pipes were converted to an BIM/IFC model. The models from both cases were stored according to the LADM standard in a 3D LAS, represented by a 3D database and a 3D geospatial visualisation platform. The main results are that the technical part of the proposed workflow supports the registration of 3D underground objects in 3D LAS and that for underground objects the legal spaces from the 2D parcels that are extruded to 3D volumetric parcels, are sufficient enough to describe the RRRs of the objects.