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G. Navratil:
"Combining 3D Cadastre and Public Law - An Austrian Perspective";
Talk: 3rd International Workshop on 3D Cadastres: Developments and Practices, Shenzhen (invited); 2012-10-25 - 2012-10-26; in: "Proceedings", P. van Oosterom, R. Guo, L. Li, S. Ying, S. Angsüsser (ed.); International Federation of Surveyors (FIG), (2012), ISBN: 978-87-92853-01-1; 61 - 71.

3D cadastres as currently designed aim at providing information on private rights (ownership, easements, etc.). However, from an economic perspective, public-law restrictions are at least equally important because the might restrict different kinds of use on the land. This has a dramatic impact on the value of the land. Since land value is crucial for investors or credit institutes, they are equally interested in public-law restrictions as they are interested in private rights.

In addition, the 3D objects defined in a cadastre are typically seen as legally independent of each other. This is not always the case, e.g., each apartment in an apartment building must support the structure (apartments and other structure like the roof) above. This must be taken into consideration when defining separate 3D objects. The use of a public-law restriction would provide a simple solution to this.

Other regulations may have more unpleasant effects. Asking adjacent land owners to provide land for public services is a standard method in spatial planning. The extent is determined by the planned structure and may be limited by legal rules. The same would be true for 3D structures because spatial planning usually does not only deal with 2D arrangements but also with height information. It is an unfortunate situation, for example, if a small building with only a ground floor is created in an area intended (and suitable) for skyscrapers. However, compulsory purchase could have unwanted effects in 3D systems and finally leads to the question of value: What is the value of a volume floating freely in space?

3D cadastres as currently designed aim at providing information on private rights (ownership, easements, etc.). However, from an economic perspective, public-law restrictions are at least equally important because the might restrict different kinds of use on the land. This has a dramatic impact on the value of the land. Since land value is crucial for investors or credit institutes, they are equally interested in public-law restrictions as they are interested in private rights.

In addition, the 3D objects defined in a cadastre are typically seen as legally independent of each other. This is not always the case, e.g., each apartment in an apartment building must support the structure (apartments and other structure like the roof) above. This must be taken into consideration when defining separate 3D objects. The use of a public-law restriction would provide a simple solution to this.

Other regulations may have more unpleasant effects. Asking adjacent land owners to provide land for public services is a standard method in spatial planning. The extent is determined by the planned structure and may be limited by legal rules. The same would be true for 3D structures because spatial planning usually does not only deal with 2D arrangements but also with height information. It is an unfortunate situation, for example, if a small building with only a ground floor is created in an area intended (and suitable) for skyscrapers. However, compulsory purchase could have unwanted effects in 3D systems and finally leads to the question of value: What is the value of a volume floating freely in space?

Privatrecht, öffentliches Recht, Raumplanung, Kataster, 3D