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Conceptual 3D Cadastral Model Applied in Several CountriesJantien E. Stoter, Peter J. M. van Oosterom, Hendrik D. Ploeger and Henri J. G. L. Aalders, The NetherlandsKey words: 3D Cadastre, geo-DBMS, cadastral data modelINTRODUCTIONCountries throughout the world are confronted with the complexity of cadastral registration of 3D property situations. Developments to face and solve these problems depend on the national legal system and the state of the art of the cadastral registration in the specific country. In most countries apartment rights (condominium rights) or strata titles are used to establish 3D property units. The registration of apartment rights is different in every country. However, there are no cadastral registrations known in which the spatial extent of apartment units is registered (in 2D or 3D) as part of the cadastral geographical database. International solutions to establish 3D situations involve the right of superficies or the use of easements. These rights can be spatially defined in titles or deeds by means of plans and cross sections, and in some countries also in 2D on the cadastral map (e.g. Australia, Denmark). However, no cadastral registration has been found that is able to reflect the third dimension of rights as part of the cadastral geographical data set. The disadvantage of the solutions to register 3D property units in current cadastral registration, is that the 3D information is not integrated in the spatial part of the cadastral database (only available in titles, survey plans and/or deeds). It is for example not possible to see the 3D situations of two neighbouring parcels in one visualisation. Also querying the 3D situation (’who is owner of this stratum’) is not possible. The 3D drawing in the land registration is just a (2D) visualisation of the 3D situation. Therefore it is not possible to view the 3D situation interactively. The different countries have been assessed, bearing these phases in mind, by examining the following questions:
NORWAYNorway has a solid subsurface in a geological sense. Tunnels for roads, trains, and water drilled in the subsurface do not influence the economic value of the surface property and are therefore already common practice in Norway without subdivision and formal registration in the cadastre and in the Land Book. The owners of surface properties have only been compensated financially if the surface property has been damaged in any way. In the beginning of the nineties, providing possibility for 3D property was listed as an important issue for the improvement of cadastral legislation, since the current juridical framework does not provide the establishment of 3D property units with separated ownership on one surface parcel. It was expected that investors are more willing to invest money in registered ownership, than in all kinds of limited rights that are currently used to establish stratified property. Awaiting the new law, the municipalities (which are the cadastral authorities on local level) have since many years practiced to establish properties as volumes above and under the surface, subdividing the volume from the surface property. They have extended the existing cadastral law with municipal regulations to be able to divide properties into volumes. The new regulations are based on the existing practices. An example of this practice is the municipality of Oslo. This city introduced a practical approach to register 3D properties as real property both in the cadastral registration and the title register (Valstad, 2003). These properties can be mortgaged and have rights and restrictions as surface parcels. The existing law does not provide these 3D real properties, and hence the Oslo method has mostly been limited to underground facilities. In case of a 2D subdivision, the new parcel boundaries are surveyed and marked. In the 3D case, it is impossible to survey before the actual construction has been built. Therefore the plans and drawings from the applicant are sufficient. Usually, this drawing is also accepted as the final result on which a survey certificate is issued without any surveying. On the survey certificate each corner is given in co-ordinates and heights both at the floor and the ceiling. The registration number and the survey identify the parcel as a volume, but in the various registers the parcels size is given in square meters and not in cubic metres. This is due to the Land Subdivision Act that has no provision for 3D parcels except in the accompanying text. An underground parcel is identified by a unique parcel number. Underground parcels can be recognised because the parcel number ends with '300'. The numbering of the 3D parcels is done in such a way that the relationships with the surface parcel are preserved. Evaluating 3D Cadastral Issues in Norway How can 3D property units be established within the existing juridical framework? The new law will enable to establish 3D construction properties that may cross surface parcel boundaries. Although construction property is not yet formally allowed, municipalities and the land registration already accept it, as was shown by the Oslo method. What was the main trigger to establish 3D property units or to start the discussion on how to establish 3D property units? Before the law will be enacted, stratified property can be established by apartment rights or just by the fact that the owner of the surface parcel is not obstructed in using his property. In the last case, the legal status is not established and not registered, which is always some kind of a risk, especially in case of constructions owned by private persons. Therefore it is required to ensure the legal status of real property in the cadastre. Do 3D property units exist independently in the land registration? The existence of the 3D property units is known in the land registration. However there are no requirements for surveying and mapping the 3D property unit. The 3D geometry of the property unit may therefore not be known (in detail) in the land registration. Do 3D property units exist independently in the cadastral registration? The 3D property units exist in the administrative part of the cadastral registration. The footprint of 3D construction properties can be drawn in the cadastral map. However, the 3D geometry of the 3D property unit will not be maintained. What are the main shortcomings of current registration of 3D situations? The fist shortcoming is that 3D property units are limited to constructions. Furthermore the cadastral registration can be improved by firstly setting up regulations to survey 3D property units and secondly by solving the technical aspects of 3D cadastral registration: how to incorporate the 3D information in the cadastral map? SWEDENBefore January 2004, in Sweden the division of ownership in the third dimension was not possible. This has led to remarkable legal structures. For example the space for the Stockholm underground is granted through an easement. The dominant parcel to which the easements are linked is a small property formed for a lift shaft going down to the underground railway (Mattsson, 2003). Need for 3D property has been very much influenced by the fact that apartment units in an apartment complex can only be owned totally by one housing association. Each apartment owner may sell his net share of the co-operative. The main conclusion of the committee was that the most appropriate solution would be the possibility to establish 3D property similar to 2D property. 3D properties can then be mortgaged and information on the 3D properties is accessible through the real property register. The main objection which came to the proposal was that the fundamental property concept should not be altered from 2D since the cases of 3D are limited. Therefore the new 3D properties had to fit within the structure of 2D properties. The following criteria have been set up for 3D properties:
3D property formation is only permitted if it accommodates, or intends to accommodate, a building and if it is assured of the rights necessary to its appropriate use (e.g. rights for joint facilities, easements). To avoid empty airspace property units, the 3D property has to relate to a real construction. When it is related to a construction to be built, the cadastral authority can set a deadline for the completion of the construction. Unlike in Norway a building itself may be divided into different property units. This is also the main type of ownership situation that the new law wants to facilitate. However, a 3D property for housing purposes should contain at least five apartment units, which means that the new legislation does not provide scope for the creation of apartments. Evaluating 3D Cadastral Issues in Sweden How can 3D property units be established within the existing juridical framework? The new law enables to establish 3D property units that may cross surface parcel boundaries, and must be related to constructions. What was the main trigger to establish 3D property units or to start the discussion on how to establish 3D property units? The main problem of the existing juridical system is that apartment units cannot be mortgaged independently, which may obstruct investors to invest in multi-purpose building complexes. Do 3D property units exist independently in the land registration? The 3D property units are registered in the land registration. However there are no requirements for surveying and mapping the 3D property units. The 3D geometry of the property unit may therefore not be known (in detail) in the land registration. Do 3D property units exist independently in the cadastral registration? Although 3D property units are registered as independent property units in the administrative part of the cadastral registration, it is not yet clear how 3D property units will be documented as part of the cadastral geographical data set. At this moment the projection of 3D property units can be drawn on the cadastral map. What are the main shortcomings of current registration of 3D situations? As in Norway, the first shortcoming is that 3D property units have to relate to constructions. And also in Sweden the cadastral registration can be improved by setting up regulations to survey the 3D property units and by solving the technical aspects of 3D cadastral registration: how to incorporate the 3D information as part of the cadastral geographical data set? |
Reference:FIG Working Week 2004, Athens, Greece, May 22-27, 2004www.oicrf.org/ |