Article of the Month - July 2022

3D Description of Condominium Rights in Turkey: Improving the Integrated Model of LADM and IFC

Dogus GULER and Tahsin YOMRALIOGLU, Turkey
Dogus Guler Tahsin Yomralioglu


This article in .pdf-format (27 pages)

This article improves the previous conceptual model that links the classes of LADM and entities of the IFC schema such that it covers a detailed delineation of condominium rights. The models that cover packages of LADM and the related code lists are presented. This study contributes to the 3D LASs transition in Turkey by providing a significant basis for IFC-based modeling of condominium rights. The paper will be presented in the FIG Congress 2022 in Warsaw Poland

In 2021 Dogus Guler received the FIG Foundation Ph.D. scholarship incl a travel grant to the FIG Congress to present this successfully peer reviewed paper.


Efficient management of land is vital for sustainable development. The growing densification in the built environment however makes difficult the job of land administration. In addition, the built environment now contains a large number of buildings and facilities that are complex and multilayered. In this sense, Land Administration Systems (LASs) are of great importance to cope with emergent problems that should be paid attention to for economic, social, and environmental aspects. It is for this reason that three-dimensional (3D) LASs that enable to unambiguously delineate the cadastral Rights, Restrictions, and Responsibilities (RRRs) with their physical counterparts are a hot topic. On the other hand, digitalization has gained a lot of attention all around the world for improving and facilitating the processes regarding both public services and different sectors such as Architecture, Engineering, and Construction (AEC) industry. Considering the AEC industry is one of the primal sectors that implement the alterations in the built environment, there exists a close relationship between this industry and the land administration sector that deals with efficient management of the built environment. Today’s AEC industry is performing a huge effort for the adaptation of Building Information Modeling (BIM) that allows to create highly detailed models of buildings and their immediate surroundings with semantically and spatially rich information. Whereas the Land Administration Domain Model (LADM) provides a conceptual model for land administration practices, Industry Foundation Classes (IFC) enables the interoperability in terms of construction/building modeling through its comprehensive schema that contains a great number of entities. It is thus important to benefit from the (as-built)building models for registration and depiction of condominium rights in Turkey. This paper, therefore, improves the previous conceptual model that links the classes of LADM and entities of the IFC schema such that it covers a detailed delineation of condominium rights. The models that cover packages of LADM and the related code lists are presented. This study contributes to the 3D LASs transition in Turkey by providing a significant basis for IFC-based modeling of condominium rights.


Information regarding the land is highly important for countries since it contributes to development in terms of various aspects such as economic, cultural, legal, and social. Land registry and cadastre is the paramount issue that provides and preserves this kind of information completely (Yomralioglu and McLaughlin, 2017). Land administration aims to benefit from the information with respect to land and water, and Rights, Restrictions, and Responsibilities (RRRs) that are subject to it. The importance of land administration also appears in the sustainable development goals and targets, for example, goal 11, which is to make cities and human settlements inclusive, safe, resilient, and sustainable (United Nations, 2015). Land Administration Systems (LASs) that enable the management of the ownership information with their spatial components together are implemented such that they focus on two-dimensional (2D) data (Kalogianni et al., 2020). However, ownerships regarding underground and aboveground of land should be considered and integrated into LASs. In addition, the built environment is now more complex and denser than ever before globally. The challenges for the registration of RRRs on buildings and facilities on the land are therefore notably increasing (van Oosterom, 2018; Williamson et al., 2010). Evolving the LASs in a way that they have the capabilities to manage, store, analyze, visualize, and disseminate ownership rights in three-dimensional (3D) is considered an important solution to cope with these challenges (van Oosterom et al., 2020). It is important to mention that the term 3D land administration is taking the place of the 3D cadastre notion because it encompasses the cadastral and land registry activities as a whole (Kalogianni et al., 2020). The need for the conceptual basis that facilitates the 3D land administration is fulfilled with the publication of the Land Administration Domain Model (LADM) Edition I as an International Organization for Standardization (ISO) standard 19152 (ISO, 2012). Countries concentrate to develop their models that are modified by taking as a reference the LADM (Kalogianni et al., 2021). Creating a country profile of the LADM is of significance since the legal basis and implementation approach with respect to land administration differs within countries and jurisdictions. Condominium ownership that can be formed in the units of the building that are suitable to exploit independently is a special type of ownership. In the context of 3D land administration, there is a need for the registration and representation of condominium rights in great detail. Noteworthy to mention that there are various types that can be subject to 3D land administration such as tunnels, utilities, and mining; however, this paper zooms in on buildings/condominiums. Spatial data standards that enable to the model of physical objects in the built environment in 3D are of importance to delineate the condominium rights in buildings or facilities. CityGML, as an Open Geospatial Consortium (OGC) standard, provides Geography Markup Language (GML)-based model for creating 3D models in different themes such as building, land use, and transportation (OGC, 2021). It is thus practiced by a large number of scholars to model legal rights with physical counterparts within buildings (see (Guler and Yomralioglu, 2021a)). In this regard, Sun et al. (2019) presented an example to use the CityGML 3.0 for 3D cadastre purposes. Geoinformation that constitutes the vital basis for Geographic Information Systems (GIS) is exploited considerably in the land administration domain and its related fields such as spatial planning (Indrajit et al., 2020), urban management (Lemmen et al., 2015), and real estate valuation (Kara et al., 2021, 2020; Mete et al., 2022). The Architecture, Engineering, and Construction (AEC) industry intersects with the land administration sector because it should be conformed to decisions on how land should be used before designing and constructing a completely new building or transforming an existing building. In the AEC industry, Building Information Modeling (BIM) that provides to create 3D models of buildings and immediate surroundings detailedly through object-based modeling techniques that allow storing spatial information and semantic information is replacing of traditional Computer-Aided Design (CAD) (Teicholz et al., 2018). Statistics show that the use of BIM has become widespread in many countries (BIMgenius, 2020; McGraw Hill Construction, 2014; NBS, 2020). BIM models (BIMs) are also significant for digital transformation that should be paid attention to by administrations for facilitating and improving public services such as building/construction permitting (Guler and Yomralioglu, 2021b; Noardo et al., 2020b). Considering the as-built BIMs of buildings will be existing, there is a highly promising opportunity to use these BIMs for implementing 3D LASs (Broekhuizen, 2021; Meulmeester, 2019; Oldfield et al., 2018, 2017, 2016; Rajabifard et al., 2019; Ramlakhan et al., 2021). Researchers from different countries hence focus on the modeling of RRRs in the buildings and immediate surroundings using BIMs (see (Guler and Yomralioglu, 2021a)). This paper aims to improve the initial conceptual model (Guler and Yomralioglu, 2021a) in a way that integrates LADM and Industry Foundation Classes (IFC) for thoroughly representing the condominium rights in Turkey by considering legal spaces and detailed building elements as well. The purpose of the model is to enable the IFC models that contain and provide physical objects with the required semantics for 3D representation of condominium rights. The integrated model can be utilized by land registry and cadastre agencies for registering and disseminating cadastral information and also by architects/designers as a guideline in creating building models in a way that includes legal spaces. The paper continues with the background section providing information on the standards. The subsequent section informs readers about the current situation in Turkey. Section 4 presents the integrated model in this study. The last section discusses the advantages of the model in terms of 3D land administration and concludes the paper.



2.1 Standards

2.1.1 Land Administration Domain Model (LADM) ISO 19152:2012

LADM is an ISO standard that provides a conceptual model for land administration practices. The main aim of the standard is to ease the transition to an efficient land administration system by benefiting from the standardized model that encompasses a wide range of components involving land administration. The conceptual schema of the LADM includes three main packages namely Party, Administrative, Spatial Unit, and one sub package of Spatial Unit as Surveying and Representation. Whereas the Party package allows to model different types of parties that involve land administration practices, the Administrative package provides classes that can be used to detailedly represent specific occasions and elements with respect to RRRs. The Spatial Unit package of the schema describes how to model features that should be delineated spatially. The land parcel, buildings, and infrastructure facilities are examples of features that can be modeled within this package. The goal of the Surveying and Representation package is to provide an efficient spatial modeling concept for features in the Spatial Unit package. LA_BoundaryFaceString, LA_BoundaryFace, and LA_Point are the classes that are created to represent LA_SpatialUnit instances. The geometries of these classes are GM_MultiCurve, GM_MultiSurface, and GM_Point respectively. It is significant to note that LADM benefits from ISO 19107 standard that provides a spatial schema for geographic information, in order to obtain geometry specifications in the conceptual model. There is an ongoing activity on preparing the next version of LADM. The updated version of LADM will contain new parts, including Valuation Information (Part 4) and Spatial Plan Information (Part 5) (ISO/TC 211, 2021), so as to cover all main components of land administration. It is also aimed to improve the modeling of 3D spatial units. There is additionally an ambition to provide fundamental steps for the transition to the implementation (Part 6) from conceptualization in the context of the revision of LADM (Kalogianni et al., 2021).

2.1.1 Industry Foundation Classes (IFC) ISO 16739-1:2018

IFC is the primary, open standard for BIM data (buildingSMART, 2022). This standard is developed by buildingSMART to provide interoperability regarding data exchange between different stakeholders and software in construction or facility management. IFC provides a comprehensive schema that enables to digitally represent the whole lifecycle of buildings and facilities. IFC contains four main data schemas namely core, shared element, domain-specific, and resource definition. These data schemas include a great number of defined types, enumeration types, select types, entities, functions, rules, property sets, quantity sets, and individual properties (buildingSMART, 2022). IfcRoot is the root entity in the IFC schema. IfcProject is the main entity that enables to store of information about the project such as location and coordinate reference system. IfcActor, as a subtype of the IfcObject entity, enables to record information with regards to actors involved in a project lifecycle. The actors can be a person or an organization. IfcSpatialElement and IfcElement are two of the subtypes of the IfcProduct entity. IfcElement has several subtypes such as IfcGeographicElement, IfcDistributionElement, IfcCivilElement, and IfcBuildingElement. These entities provide modeling specifications for the different elements that might be in building or facility projects. For example, IfcGeographicElement can be used to model different kinds of features related to landscape. IfcBuildingElement is the primal entity that is used to store a wide range of elements regarding buildings. Doors, beams, columns, stairs, walls, windows are examples of these elements. IfcSpatialElement has three subtypes as IfcExternalSpatialStructureElement, IfcSpatialStructureElement, and IfcSpatialZone. IfcExternalSpatialElement, as a subtype of IfcExternalSpatialStructureElement, enables to model of the external regions of the building site logically or physically. IfcSpatialStructureElement has four subtypes namely IfcSite, IfcBuilding, IfcBuildingStorey, and IfcSpace in order to define the possible spatial elements for different structure levels of buildings. There exists the aggregation relationship between these subtypes through the IfcRelAggregates entity. The current version of IFC is IFC4 ADD2 TC1 however there is an ongoing activity for developing the IFC (4.3).


3.1 Legislative Background

There are several laws and legislative documents regarding land administration and cadastral registration in Turkey. Turkish Civil Code No.4721 (Official Gazette, 2001) is the main law that describes real estate ownership. It is stated in Article 704 of this law that the subjects of real estate ownership are land, independent and permanent rights that are recorded on the separate pages of the land register, and condominiums that are recorded to the condominium register. This article manifests the condominium rights officially. The Civil Code also contains a number of articles that describe a wide range of rights such as superficies, usufruct, and right of way. In addition to the Civil Code, Cadastre Law No.3402, Land Registry Law No.2644, and Zoning Law No.3194 are the important legal references for cadastral registration. Condominium Law No.634 (Official Gazette, 1965) is the main legislative document that defines the RRRs with respect to condominiums. Article 1 of the Condominium Law states that independent ownership rights can be established by the owner or joint owners on the different units such as storey, apartment, office, store, cellar, and storage of a constructed building that are suitable to be used independently and separately. Clause 1 of Article 2 of the same law provides the definitions of the main real estate, main building, condominium, annex, condominium right, and condominium owner. According to the law, a condominium owner can have the right to use on condominium itself and spaces that are in the outside of the condominium as well. Annexes can be coal cellar, water tank, garage, electric meter box, or toilet. The Condominium law also states that condominium owners have jointly right to use on shared facilities and spaces that are in the outside of the condominiums in real estate and serve for protection and exploitation. Main walls, beams, columns, curtain walls, floors, ceilings, patios, stairs, elevators, and corridors are examples of shared facilities and spaces. Noteworthy to mention that 2D representations might be insufficient to realistically delineate the condominium rights in multilayered buildings. Building permitting is another important issue for condominium rights because it is mandated in the Condominium Law that the condominium plans that are approved in the occupancy permit procedure should be used for the registration of condominium rights after the construction of the building (Guler and Yomralioglu, 2021c).

3.2 Recent Advancements

3.2.1 Academic Works

First efforts with respect to 3D cadastre in Turkey started with academic studies. There are a couple of graduate theses regarding the establishment of a database for 3D cadastre (for example, (Döner, 2010)). Afterward, a CityGML ADE that covers the modeling and storing of the condominiums is proposed with the aim of taxation (Cagdas, 2013). Döner & Şirin (2020) examine the 3D cadastre approaches in Turkey in terms of legal, technical, and organizational aspects. With the publication of the LADM as an ISO standard, a country profile for the management of 3D RRR is developed by researchers (Alkan et al., 2021). In addition, an ADE for 3D cadastre purposes in Turkey is created by benefiting from the integration of LADM and CityGML (Gürsoy Sürmeneli et al., 2022). Scholars use CityGML 2.0 in their studies. An implementation that focuses on the real estate valuation in the context of the developed LADM Valuation Information Model (VIM) is also shown (Kara et al., 2021). The VIM contains modeling of condominiums and their attributes so as to use for valuation purposes. Guler & Yomralioglu (2021b) underline that it can be exploited interrelation between digital building permitting and registration of condominium rights through exchanging 3D digital models such as BIMs. Celik Simsek and Uzun (2021) propose to use of BIMs to model condominium rights and to find the values of condominium units for calculating the land share. Recently, an initial conceptual model that benefits from IFC and LADM standards to delineate the condominium rights in Turkey is developed (Guler and Yomralioglu, 2021a). The abovementioned studies mainly focused on the use of LADM and CityGML standards for representing the vertical ownership rights in Turkey even though the international research agenda concentrates on the opportunity that results from benefiting the BIM/IFC models recently. There is thus a strong need for a model mapping in Turkey that enables obtaining the semantics regarding condominium rights with their physical components by using the BIM models in the context of realizing the 3D LAS. The approaches that were proposed to model the property rights by means of standards such as CityGML and LADM can be exploited to develop a complete model connecting LADM and IFC.

3.2.2 Governmental Projects and Strategies

The 11th Development Plan, which is the current plan, contains the completion of the multidimensional cadastre. It covers the publication of the digital, up-to-date, and trustworthy cadastral data in order to create the basis for investments that are made by public and private sector organizations. The plan also underlines that ownership data will be transferred to the electronic environment. “2020-2023 National Smart Cities Strategy and Action Plan” is of significance because it highlights that BIMs will be used in building permitting procedures. This means that there will be an important opportunity to use of BIMs in cadastral registration.
Before the 3D modeling of cadastral rights, it is aimed to create a national Spatial Data Infrastructure (SDI) for Turkey. Interoperable spatial data production by a wide range of public organizations is highly essential for establishing and maintaining SDI. For this reason, the Turkey National Geographic Information System (TNGIS) project is carried out by the General Directorate of Geographic Information Systems (GDoGIS). Within the project, the conceptual models and their application schemas for various themes such as building, cadastre, and land use are developed based on the Infrastructure for Spatial Information in the European Community (INSPIRE) data specifications and shared. These conceptual models and application schemas are updated in specific periods. While the previous versions of the Building Theme contain only 2D-based building models, the new version of this theme will cover the 3D building models that are modeled as a CityGML ADE based on the latest version of the CityGML standard (MoEUCC, 2021). With the increasing international attention for 3D cadastre, the project titled “3D Urban Models and Cadastre” is started to carry out by the General Directorate of Land Registry and Cadastre (GDoLRC). Whereas one aim of the project is to create 3D digital models of cities, the other aim is to produce 3D building models that store and represent the cadastral rights. Within the project, 2D floor plans are digitized and labeled in CAD software. Afterward, these CAD files are converted to CityGML 2.0 files by populating cadastral rights in the buildings.


In this study, a conceptual model that is developed previously is improved such that it provides to model condominium rights in buildings more completely. Two ISO standards namely LADM and IFC that are widely accepted are used for developing the model. Figure 1 presents the Party and Administrative packages of the developed model. As can be seen from Figure 1, all features in the Party and Administrative packages of LADM are utilized in the model. TR_Party has twelve attributes that are needed in cadastral registration. It has four attribute defined by code list as TR_NationalityType, TR_PartyType, TR_IDType, and TR_PartyRoleType. The different parties involved in the registration of condominium rights can be delineated using TR_Party. There are generalization and aggregation relationships between TR_Party and TR_ GroupParty classes. TR_ GroupParty can be used to model the parties that represent a number of parties as a whole. TR_RRR has three subclasses namely TR_Responsibility, TR_ Right, and TR_Restriction. RRRs that can be subject to a condominium can be depicted using these classes. TR_Mortgage that might be applied to a specific condominium has an association relationship with TR_Right and a generalization relationship with TR_Restriction. TR_AdministrativeSource class has four attributes namely journalNumber, registrationDate, volume, and pageNumber that store the necessary information for cadastral registration. It is important to note that some of this information comes from the non-digital registration of cadastral rights. TR_Right has an attribute namely TR_RightType that provides different types such as superficies, usufruct, and timeshare. TR_BAUnit, which represents the registration object in the Turkish land administration system, has an attribute type as TR_BAUnitType that enables to select parcel, building, or condominium. Figure 2 demonstrates the code lists that are prepared for attributes of Party and Administrative packages. It is possible to add new property sets to IFC entities in a BIM authoring tool. Table S.1 itemizes the property set names, property names, property types, and data types that can be used to store the attributes of the classes in the Party and Administrative packages of the developed model. It is important to note that the IFC file would not be complete without these properties. There are several entities in the IFC schema to use in the representation of the classes in the developed model. IfcActor entity that expresses the persons or organizations involved in a project can be used to model TR_Party. More than one IfcActor instance can be modeled as IfcGroup through the IfcRelAssignsToGroup entity. In this way, TR_GroupParty class can be depicted by using IfcGroup. IfcDocumentInformation that is aimed to store metadata information for an external document can be utilized to represent the TR_AdministrativeSource class. IfcZone is an entity that enables to the group of multiple spaces. It can be used to model different legal spaces that belong to a condominium. Furthermore, source information of cadastral registration can be linked to the registration object via the IfcRelAssociatesDocument entity.

Figure 1. Party and Administrative packages of the developed model.

The different building elements can be subject to a condominium as an instance of TR_BAUnit class. In this case, different building element instances can be grouped using the IfcBuildingSystem entity. To model the TR_RRR, TR_Responsibility, TR_Restriction, TR_Right, and TR_Mortgage classes, the relationship between IfcActor, IfcDocumentInformation, IfcZone, and IfcBuildingSystem can be benefited. By doing so, the information about which actor is responsible for what kind of RRR can be stored in the database. Whereas IfcActor can be enhanced with the attributes of TR_Party, IfcGroup is suitable for being added attributes of TR_GroupParty. The property set pertaining to TR_AdministrativeSource can be included in IfcDocumentInformation.

Figure 2. Code lists for the Party and Administrative package of the developed model.

Figure 3 shows the Spatial package and Surveying and Representation sub package of the developed model. Figure 4 demonstrates the code lists that are prepared for the Spatial package and Surveying and Representation sub package of the developed model. TR_SpatialUnit is an abstract class that has three subclasses namely TR_Parcel, TR_Building, and TR_BuildingElement. TR_Parcel class has seven attributes that provide necessary information regarding the land parcels for the cadastral database. Two of them are defined by code list namely TR_ParcelType and TR_LandUseType. TR_Building that has an association with TR_Parcel represents the buildings that can be constructed in a parcel. It has a great number of attributes that might be beneficial for different applications such as urban regeneration. TR_CondominiumUnit is one of the crucial classes that is utilized to condominium rights. It has an aggregation relationship with TR_MainUnit, TR_Annex, and TR_SharedFacility. There is a composition relationship between TR_CondominiumUnit and TR_Building classes since one condominium unit should be existing at least to be composed of condominium rights within a building. TR_MainUnit has a good number of attributes that provides information with regards to the apartment unit. As mentioned before, a condominium can have different accessory parts such as a water tank, coal cellar, and storage according to the Condominium Law. This is why TR_Annex class has an attribute namely relatedUnitNumber in order to assign the external legal spaces to the related condominium. It has also the TR_AnnexType attribute type to enable the defining the particular accessory types. TR_SharedFacility class has an attribute type namely TR_SharedFacilityType that represents the different facilities and spaces that are exploited in common, for example, elevator, corridor, and swimming pool. TR_BoundaryFace has an association with TR_CondominiumUnit for delineating the faces of condominium units. TR_BoundaryFaceString is utilized to represent the boundaries of land parcels. TR_Point has associations with TR_BoundaryFace and TR_BoundaryFaceString as well. TR_BuildingElement class is used to express the building elements such as walls, doors, and columns that can be subject to condominium rights. There is a composition relationship between TR_BuildingElement and TR_Building classes. Whereas relatedUnitName and relatedUnitNumber provide information about which condominium unit has the right to use on which specific building element, buildingElementType is exploited to store the element type. In the IFC schema, IfcBuildingElement has many subtypes to depict the different building elements.

Figure 3. Spatial package and Surveying and Representation sub package of the developed model.


Figure 4. Code lists for Spatial package and Surveying and Representation sub package of the developed model.


Figure 3 illustrates the selected entities that can be used to model condominium rights pertaining to building elements. The reason for showing the association between TR_CondominiumUnit and IFC entities regarding these elements is that condominium units can have different building elements. It is important to note that each element in a building are modeled only one time as a TR_BuildingElement instance. In other words, aforementioned attributes such as relatedUnitName and relatedUnitNumber are exploited for RRR regarding a building element. As mentioned before IfcSpatialStructureElement has four subtypes. One of these subtypes is IfcSite can be used to represent land parcels. It can be noted that IfcSite is defined as an area of land in the IFC schema. Another subtype is the IfcBuilding entity that can be used to delineate TR_Building class in the model. IfcSpace is another subtype that is provided to model areal or volumetric spaces that are defined logically or physically. It is feasible to model legal spaces regarding condominium units. In this way, TR_MainUnit, TR_Annex, and TR_SharedFacility classes can be also represented via IfcSpace. To delineate all spaces that the condominium has the right to use, the IfcZone entity that represents the group of spaces can be utilized. The space boundaries can be represented using IfcRelSpaceBoundary that allows expressing boundaries of spaces virtually or physically through IfcConnectionSurfaceGeometry. In this way, it can be depicted what condominium is responsible which faces of the wall. Whereas IfcCartesianPoint, as a subtype of IfcPoint, is feasible for describing TR_Point. IfcPolyLine can be used to model the TR_BoundaryFaceString class. The property sets regarding TR_MainUnit, TR_Annex, and TR_SharedFacility can be added to the IfcSpace entity. Whereas the property set of TR_Parcel is suitable for being added to IfcSite, IfcBuilding can be enhanced with the property sets of TR_Building. The property set of TR_BuildingElement can be added to subtypes of IfcBuildingElement that are included in the developed model. Table S.2 lists the property set names, property names, property types, and data types that can be used to store the attributes of the classes in the Spatial package and Surveying and Representation sub package of the developed model. While IfcPropertySingleValue can be used for the attributes that have a single value such as integer and string, IfcPropertyEnumeratedValue is suitable for attribute types that can be selected from a defined list.


This paper presents the improved version of the conceptual model for delineating the condominium rights in Turkey. The model exploits LADM as a basis for modeling the semantically and spatially necessary classes in the representation of condominium rights in a realistic manner. To benefit from the opportunity that results from being designed the buildings using BIM, existing classes are linked to suitable entities in the IFC schema to depict the condominium rights. These entities enable to unambiguously model the buildings and their immediate surroundings as well as the logical spaces that the condominium owner has the right to use. It is important to note that the use of specific entities and relationships between them might differ based on the legislative regulations of the countries or administrations regarding registration and definition of condominium rights. It is however shown in this paper that the reuse of as-built BIMs can be highly beneficial in the registration and visualization of condominium rights with their physical counterparts in Turkey, as similarly demonstrated in the literature on various study regions (Atazadeh et al., 2017). Statistics, governmental visions, and literature together show a growing trend for digitalization in the AEC industry through the efficient and widespread use of BIM. This study therefore specifically focuses on the use of IFC models in the depiction of condominium rights in the context of 3D land administration evolvement.

Another reason for concentrating on the use of BIMs is due to challenges regarding the integration of GIS and BIM domains. Recent studies point out that although there exists a vast amount of progress for integration between GIS and BIM-based models through being revised standards in terms of modeling approaches, the flowless transformation is not at the expected level in terms of georeferencing, accuracy, and consistency (Noardo et al., 2020a). Accordingly, it should be paid attention to prospective conversions between GIS and BIM-based models within information flow regarding the registration of condominium rights. The representation of the IFC models that current or prospective condominium owners can detailedly view and explore their cadastral rights as 3D is a crucial part of 3D LASs because in this way the probable misinterpretations that might cause problems within land administration practices can be hindered.

As it is known, land valuation and land development are significant elements of the land administration paradigm, and hence LADM Edition II will cover these elements by adding two new parts namely VIM and Spatial Plan Information. It is thus important to first highlight that there is a huge potential to estimate values of condominium units by means of IFC models that provide a large amount of information regarding attributes that affect the value. A few studies (e.g., (Mete et al., 2022)) focus on the likely use of IFC models for valuation and/or taxation but this can be enhanced in future studies. Secondly, it is vital to investigate the usability of IFC models for spatial planning purposes since the urban planning checks that restrictions are specified in approved zoning plans are one of the first processes within building permitting (Noardo et al., 2022). In this sense, the conceptual model that can benefit from the IFC schema, and related property sets can be extended by taking valuation and spatial planning paradigms into account. By doing so, the conceptual model that encompasses all components of 3D land administration can be achieved.


The first author is supported by the FIG Foundation PhD Scholarship. This work is supported by the Scientific Research Projects Department of Istanbul Technical University (Project Number: MDK-2019-42092).


Supplementary material can be found at:


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Dogus Guler is a research & teaching assistant at the Department of Geomatics Engineering of Istanbul Technical University (ITU), Turkey. He obtained BSc and MSc degrees in 2015 and 2016, respectively, and is pursuing his PhD at the same department. He published several papers on 3D land administration and GIS-aided urban planning. He worked on different projects that are supported by The Scientific and Technological Research Council of Turkey (TUBITAK). He was a visiting researcher for a year at the University of Colorado Boulder, USA starting from August 2019 through International Research Scholarships for Research Assistants (YUDAB) by the Turkey Council of Higher Education (YOK). He is also awarded the FIG Foundation PhD Scholarship in 2021.

Prof. Tahsin Yomralioglu graduated from the Department of Surveying Engineering of Karadeniz Technical University (KTU), Trabzon, Turkey, in 1985. He worked on Land Information Systems at the University of New Brunswick (UNB) in Fredericton, Canada. In 1993, he obtained his PhD from the University of Newcastle upon Tyne, England. First, he was appointed as a full-time professor at KTU in 2001 and then at Istanbul Technical University (ITU) in 2009. He has been served as a member on various commissions and also worked as a project manager and consultant in several public and private institutions. As a supervisor, he supervised over 30 MScE and PhD theses. He established the ITU-GeoIT graduate programme and the first national GIS R&D innovation center of Turkey. He has published many scientific research publications in the field of GIS, SDI, cadastre, land management, etc.


Dogus Guler
Department of Geomatics Engineering, Istanbul Technical University
Maslak Campus, Civil Engineering Faculty, 34469
Istanbul TURKEY

Tahsin Yomralioglu
Department of Geomatics Engineering, Istanbul Technical University
Maslak Campus, Civil Engineering Faculty, 34469