In this paper, an overview of property valuation system and practices in the Netherlands are described within the context of LADM Valuation Information Model. The paper also includes the development of the Netherlands Country Profile of LADM Valuation Information Model. A collaborative research initiative has proposed an international valuation information model that extends the ISO 19152:2012 Land Administration Domain Model (LADM) for specifying semantics of valuation registries maintained by public authorities. The proposed model was created based on the specifications of international standards; literature survey and data acquired from questionnaires responded by the national delegates of FIG Commission 9 and FIG Commission 7. Recently, the model has been updated according to the outputs of the seventh LADM Workshop, information gained from personal communications, and the results of previous tests and assessments. It has been decided that the model should be evaluated with new country profiles and prototype systems. This paper firstly examines the public property valuation system and practices in the Netherlands in terms of property valuation legislation, WOZ-value (the official assessed value), the usage areas of the WOZ-value, valuation approaches, revaluation, indexing and dissemination of the WOZ-values. Secondly, the required data sets for property valuation and their data sources are identified considering the related legislation and the System of Key Registers in the Netherlands. The obtained information is used to develop the Netherlands Country Profile of the LADM Valuation Information Model. It is noted that the country profile covers transaction prices used in valuation procedures, parties involved in valuation practices, and market analysis information. It is proved that LADM Valuation Information Model provides a decent basis to represent property valuation system in the Netherlands. The results of the study will be used to evaluate LADM Valuation Information Model and input will be provided to LADM v2.0 revision within ISO TC 211 and OGC.@en

ISO standards, which are actually being applied, are subject to periodic revision, typically in a 6 to 10-year cycle. A UN-GGIM Meeting of the Expert Group on Land Administration and Management was held on 14-15 March 2017, in Delft and the main conclusion was that the revision of LADM was indeed needed in order to provide better tools to improve tenure security and better land and property rights for all. It was also noted that land administration is a rather complex domain, and thus the revision will involve many stakeholders, namely: ISO, FIG, OGC, UN-Habitat, UN-GGIM, World bank, GLTN (Global Land Tool Network), IHO, RICS, etc.. Further goals of the revision include: providing reliable Land Administration Indicators for the Sustainable Development Goals (SDG), developing standard(s) supporting a Fit-for-Purpose approach, paying attention to implementations and tools (not just conceptual model), and inclusion of valuation information (which might help to define/support the Fit-for-Purpose approach). In order to prepare the LADM revision, two workshops were organized: 16-17 March 2017 (Delft) and 11-13 April 2018 (Zagreb), with experts involved in the development of the initial version of LADM and representatives of all the mentioned stakeholders. For the purpose of the revision, it is important to analyze and compare currently operational and proposed country profiles and their implementations of the first version of LADM, ISO 19152:2012. This paper gives an overview of the status of developments and the related proposals. @en

First Edition of the Land Administration Domain Model (LADM) has three packages related to: Parties (people and organisations); Basic Administrative Units, Rights, Responsibilities, and Restrictions (of ownership rights); spatial units (parcels, and the legal space of buildings and utility networks) with a sub package for Surveying and Representation (geometry and topology). The latter sub-package provides the functionality to manage observations and cadastral surveys measurements. Contents of LADM implementations are based on authentic source documents, including the names of the persons having a role (responsibility) in the process of the initial data acquisition and/or in the maintenance process. This concerns legal/administrative data and spatial data based on field surveys and observations – where responsible professionals can be conveyors, registrars, surveyors, grassroot surveyors, citizens themselves (participatory surveying) and paralegals. Some of the existing parts of Edition I of the LADM are proposed to be refined in the context of development of Edition II of the standard. This will allow for the inclusion of better structured meta data – also in support of participatory approaches in cadastral surveying. Richer semantics may require more rigid representations of the various Code Lists and the values they contain (adding more structure and using sematic technologies to define meaning of values). An extended survey and legal models are proposed and presented in this paper. This implies adjustments from field observations to the spatial database and the generation of quality labels.@en

Standardization reduces technical barriers to trade and foster dissemination of innovations. Within the domain of information technology, standardization enhances semantic interoperability of systems and services. In order to achieve the potential of standardization, IT solutions must be localized to adapt to local needs. To reduce localization costs, software developers, but also standards develop and adopt internationalization principles and best practices, cf. the W3C Internationalization (I18n) Activity, the ISO 639 Language Codes, which provides an example for code lists and code list management, and the coding of coordinate reference systems. For the domain of Land Administration, the localization issue extends from language names to the various organizations and institutions dealing with interests in land. Paasch et al (2013) propose code lists as a mean of internationalization by which the classes of the ISO 19152:2012 Land Administration Domain Model (LADM) may be related to the concerned jurisdiction. The issue of code lists has been addressed by the OGC as well, namely in terms of the document 17-050r1 Code List Manifesto by Paul Scarponcini. Motivations for the study include that various OGC standards have encoded enumerations and code lists differently, as realized during the development of the InfraGML standard, which regards land and civil engineering infrastructure facilities, and thus share part of its scope with LADM. Aiming at harmonization of standards within the domain of Land Administration, the present paper proposes a joint management of the code lists which are specified by ISO LADM and by OGC LandInfra / InfraGML, respectively. The FIG motivated the ISO standard LADM and moreover framed research on code lists. It seems therefore appropriate to join with this organization of surveying professionals, also to benefit from sharing of expertise and cost of the management activities. The paper the outlines the tasks of code list management by drawing on the mentioned Code List Manifesto and resuming research supporting code list management, e.g. terminological theory and semantic tools. The setup of a possible code list management system is discussed, and summarized in terms of a draft Memorandum of Understanding.@en

The geometric, legal, physical, economic, and environmental characteristics of property units are utilized in valuation activities. Property valuation registries and databases are supposed to record these characteristics in relation to property units that are subject to immovable property valuation. Moreover, the links between valuation registries and the other land administration registries such as cadastre, land registry, building and dwelling should be specified. Apart from procedural valuation standards, there is no internationally accepted data standard that defines the links and semantics of property valuation databases. The ISO 19152:2012 Land Administration Domain Model (LADM), as an international land administration standard focuses on legal requirements, but considers out of scope specifications of external information systems including valuation and taxation databases. A recently started joint activity under International Federation of Surveyors (FIG) Commission 9 (Valuation and the Management of Real Estate) and FIG Commission 7 (Cadastre and Land Management) has developed an information model for the specification of valuation information maintained by public authorities especially for property taxation. This paper investigates the use of INTERLIS tools for the technical implementation of the Valuation Information Model, which has been developed as a valuation extension of ISO 19152:2012 Land Administration Domain Model (LADM). INTERLIS is a Swiss standard that enables modelling and integration of geographic data sets. It provides a conceptual schema language that can be used to specify a data model in a neutral system environment, similarly, class diagrams of the Unified Modeling Language (UML). It is compatible with international standards like UML, XML and GML. INTERLIS also provide some tools for the implementation of conceptual models into technical models. The core LADM, a number of the ISO191xx base models and some LADM country profiles were already expressed in INTERLIS standard. This paper presents definition of classes, code lists and constraints of the LADM Valuation Information Model and its Turkish Country Profile in INTERLIS. It also discusses possible advantageous of INTERLIS tools (UML editor, compiler, checker, validator and loader) such as system neutral data exchange format, compatibility with relevant international standards, reusable and extensible conceptual schema language, and automatic translation from the conceptual model to physical model.@en

Property valuation is a process of estimating value of an immovable property. The legal, geometric, physical and environmental characteristics of the immovable property together with the economic indicators are taken into consideration during this process. Traditional cadastral systems only provide two-dimensional (2D) legal and geometric information about property units. However, today’s complex valuation practices (e.g. computer aided mass appraisal) would benefit significantly from three dimensional (3D) information on not only property units but also their physical counterparts (e.g. buildings, building parts). Moreover, 2D and 3D environmental information is needed for determining environmental conditions about immovable properties to better estimate the values of them. A collaborative research initiative has proposed an international valuation information model that extends the LADM for specifying semantics of valuation registries maintained by public authorities. The current version of the LADM Valuation Information Model, however, does not include detailed specification for the environmental characteristics of immovable properties (e.g. presence of views, level of visibility and distance to amenities) which can be derived with 2D and 3D geospatial analyses by means of various data sources. The purpose of this paper is to examine which geospatial analyses, especially 3D analyses, can be used to provide information about immovable properties including environmental and locational characteristics for property valuation activities. Furthermore, it is investigated that how property valuation can benefit from data sources including semantically rich 3D building, city and cadastral models for deriving environmental and locational characteristics of property units. To achieve these objectives, the data sources and geospatial analyses are initially investigated in the context of property valuation. Then, the paper focuses more on viewshed analysis. By using open topography, building and height datasets of the Netherlands and 3D GIS analysis, a viewshed analysis is presented to show how it can be utilized using different data sources for better understanding and explanation of values of the properties. The paper is concluded with a discussion to what extent it is possible and meaningful to include (derived) environmental characteristics of properties in the LADM Valuation Information Model.@en

A recently established joint working group under International Federation of Surveyors (FIG) Commission 9 (Valuation and the Management of Real Estate) and FIG Commission 7 (Cadastre and Land Management) has started the development of an information model for the specification of valuation information maintained by public authorities especially for property taxation. In this initiative, ISO 19152:2012 Land Administration Domain Model (LADM) has been taken as the basis for the development of a Valuation Information Model. A first version of the LADM Valuation Information Model was created based on international standards, literature survey and data gained from questionnaires replied by the national delegates of FIG Commission 9 and FIG Commission 7. The planned further works include (i) creating country profiles, and (ii) development of prototypes for the assessment of country profiles and conceptual model itself. This paper presents an overview of immovable property valuation conducted for taxation purposes in Turkey. Based on this overview, it also proposes a country profile of LADM Valuation Information Model in Turkey case. The country profile covers valuation activities for annually levied recurrent property taxes (i.e. Land Tax and Building Tax) in Turkey, characteristics and spatial aspects of valuation units used in property valuation, property valuation approaches employed for property taxation, transaction prices used in valuation procedures, parties involved in valuation practices, and information on taxes on immovable property. The profile also includes the content of code lists that detail administrative valuations in relation to property tax assessments in Turkey. The proposed profile is evaluated with Unified Modeling Language (UML) instance level diagrams in examples of property taxes on land and building in Turkey for assessing whether the profile fulfills the needs of information management aspects of valuation activities for property taxation. Towards@en

Processes and transactions in Land Administration are outside the scope of the Land Administration Domain Model Edition I published in 2012. Reason is that processes were considered to be country specific. Generic processes would be too difficult to model. This view needs reconsideration – given developments as Fit-For-Purpose Land Administration, Apps and blockchain. In many countries different organizations have their own responsibilities in data maintenance and supply, but may communicate on the basis of standardised administrative and technical update processes. Operationalisation and implementation of LADM requires attention to this aspect - at least at conceptual level (not prescriptive). This will an issue in the development of LADM Edition II and this is the issue that is explored in this paper.@en

Dense urbanisation has led to an increasing demand and pressure for land development, resulting in the partition of 3D space into different owners sharing delimited property interests on, above or below the land surface. Consequently, cadastral spatial units range from simple, but most common, 2D, to complex 3D collections of spaces worldwide, that are more difficult to handle in terms of surveying, storing in a database, maintaining, visualising, etc. Subsequently, this asks for the categorization and organization of the different types of spatial units that are physically identified and legally recognised in various jurisdictions worldwide. In the context of the Land Administration Domain Model (LADM) (ISO 19152, 2012), the “level” concept (LA_Level class) provides a framework for organising the different types of spatial units. Based on that, five levels of encoding are defined in ISO19152, providing a framework of categorisation of 2D spatial units, represented by five spatial profiles included in Annex E of ISO 19152. Six years after the publication of the first edition of LADM as ISO standard, a lot of research has been carried out by experts from all over the world, and today, the ground seems to be mature for the LADM (edition I) revision, which started in May 2018, as a joint activity with many stakeholders involved (ISO TC211, OGC, FIG, etc.). One of the goals of the revision, among others, is to improve LADM’s current 3D support. This can be achieved through the design of new 3D spatial profiles for the different types of spatial units that are recognised by cadastral authorities in various jurisdictions. New and different 3D spatial units’ types may be considered for inclusion in the standard. To this end, the aim of this paper is to investigate, examine and review - in the context of LADM revision- the different types of real-world spatial units, as they have initially been organised by Thompson et al (2015). Based on the revised taxonomy, spatial profiles for the spatial units’ categories are introduced and (several) are further explored and designed. Hence, the focus on this paper lies on two levels: the taxonomy and the spatial profiles, while the level of encoding is not included in the scope of this paper. However, the investigation of the technical encodings that will be used for the implementation of the 3D spatial profiles is introduced at the paper as future work, underlying its importance. Within this concept, the scope and ambition of LADM revision are discussed.@en

Processes and transactions in Land Administration are outside the scope of the Land Administration Domain Model Edition I published in 2012. Reason is that processes were considered to be country specific. Generic processes would be too difficult to model. This view needs reconsideration – given developments as Fit-For-Purpose Land Administration, Apps and blockchain. In many countries different organizations have their own responsibilities in data maintenance and supply, but may communicate on the basis of standardized administrative and technicalupdate processes. Operationalization and implementation of LADM requires attention to this aspect - at least at conceptual level (not prescriptive). This will an issue in the development of LADM Edition II and this is the issue that is explored in this paper. @en

This paper presents the first and incomplete draft text for the revision of IS 19152:2012 ‘Geographic information — Land Administration Domain Model (LADM)’ within ISO TC211 in the form of a New Working Item Proposal (NWIP). This ‘two-page NWIP’ text aims to describe the scope of proposed project to revise, and also provides the purpose and justification behind this revision of LADM. The International Federation of Surveyors (FIG) also submitted to ISO the NWIP for the current version of LADM (IS 19152:2012). As for the revision the ambition is now to go beyond just a conceptual model by providing steps towards implementations (e.g. more specific profiles, technical model in various encodings, etc.), it is the intention that the Open Geospatial Consortium, Inc. (OGC) is heavily involved in the revision and that the result is a joint ISO/OGC standard. For this purpose the recent draft OGC White Paper is added as Appendix 1 to this paper to provide more detail background information. It is further noted that the complete NWIP for Edition II of LADM also ‘Preparatory work’ should be attached; e.g. a draft of the new version of the standard. In the case of the revised LADM standard of course this is based on the IS 19152:2012, but will contain also contain collected materials from the LADM2017 and LADM2018 workshop.@en

Processes and transactions in Land Administration are outside the scope of the original Land Administration Domain Model (LADM) Edition I as published in 2012. Processes were considered to be country specific. By then generic processes were too difficult to model. This view needs reconsideration – given developments as Fit-For-Purpose Land Administration, Mobile Apps and blockchain processes. In many countries different organizations have their own responsibilities in data collection, data maintenance and distribution. But they all communicate on the basis of standardised administrative and technical processes. Operationalisation and implementation of LADM requires attention to this aspect, at least at conceptual level and should not be prescriptive. Nevertheless the development of the LADM is and was based on user needs. The global market and globalization are constantly influencing and introducing new processes for data collection, data maintenance and distribution all requiring a shared ontology, These administrative and technical processes will be discussed during the development of LADM Edition II. Issues in this debate will be presented in this paper. Those processes are not just transactions but the Fit-For-Purpose approach in Land Administration enables the inclusions of processes as such as: selection of imagery, automated feature extraction, initial data collection with mobile apps, etc. Also the application of blockchain for transaction management is an issue. The operationalisation of those processes and tools, at scale (apart from conventional cadastral processes which may be complex to standardise) is an issue given the ambitions in the Sustainable Development Goals to bring tenure security for all. The Open Geospatial Consortium initiated operationalisation of land administration standards as LADM and there is a cooperation with the International Standardisation Organisation in this respect.@en

This paper presents an information system artifact for the fiscal aspect of land administration, a valuation information model for the specification of inventories or databases used in valuation for recurrently levied immovable property taxes. The information model is designed as an extension module of ISO 19152:2012 Land Administration Domain Model (LADM), which is an international standard for land administration. LADM Valuation Information Model is supposed to facilitate all stages of immovable property valuation, namely the identification of properties, assessment of properties through single or mass appraisal procedures, generation and representation of sales statistics, and dealing with appeals. Therefore, it enables the recording of data concerning the parties that are involved in valuation practices, property objects that are subject of valuation, their characteristics and other datasets used for and produced within single and mass appraisal procedures. Moreover, it enables development of valuation maps, and property price records needed to assess changes in property values, as addressed by the New Urban Agenda which is as an extension of 2030 Agenda for Sustainable Development for urban areas (cf. Clause 104). The ultimate purpose of this research is to provide governments with a common basis for the development of local or national databases, enable integration of valuation databases with cadastral databases, and guide the private sector in the development of information technology products.@en

A recently started joint activity under International Federation of Surveyors (FIG) Commission 9 (Valuation and the Management of Real Estate) and FIG Commission 7 (Cadastre and Land Management) has started development of an information model for the specification of valuation information maintained by public authorities especially for property taxation. In this initiative, ISO 19152:2012 Land Administration Domain Model (LADM) has been taken as the basis for the development of a Valuation Information Model. A first version of the LADM Valuation Information Model was created based on standards, literature survey and data gained from questionnaires replied by the national delegates of FIG Commission 9 and FIG Commission 7. The conceptual model was represented through class diagrams of the Unified Modeling Language (UML). This paper describes the development of a prototype for the implementation of the conceptual model in terms of a Turkish case study. The main aim of this paper is to assess and improve the proposed conceptual LADM Valuation Information Model. In the development part, the classes, attributes, constraints, cardinalities and relations between classes of the conceptual model were converted to technical (physical) model, namely the Oracle Spatial 11g database schema has been generated from the conceptual model definitions. The conceptual schema definitions were implemented into the database, which next was loaded with sample datasets related to property valuation and taxation in Turkey. The sample data includes valuation units that are the subjects of recurrently levied property taxes in Turkey, such as unimproved urban parcel and parcel and improvements together as condominium property, valuation and taxation information of the valuation units in different years, and as well as geometries of valuation units. The technical model of LADM Valuation Information Model Turkish Country Profile has been tested in evaluation phase through SQL queries and visualization tools, respectively. In this phase, it is investigated that whether the both conceptual and technical models fulfill the needs of information management aspects of valuation activities for property taxation.@en

The challenge to develop interactive information services for new domains is supported by Knowledge Organization Systems and Services (KOS), which model the underlying semantic structure of a domain through classification systems, thesauri, gazetteers, or ontologies. The ISO 19152:2012 Land Administration Domain Model (LADM) is an international standard regarding the management of information about ownership, value and use of land. The current version of LADM addresses legal and administrative aspects; the standard revision starts in 2017, according to ISO’s periodic maintenance procedure. A group of researchers have initiated the development of a valuation component of LADM in terms of a draft extension module. It concerns the fiscal parties involved in the valuation practices and fiscal real property units that are the objects of valuation (see Çağdaş et al., 2016). The present paper aims at supporting this initiative by providing a domain vocabulary and thesaurus. The presented Valuation Thesaurus is developed according to the ANSI/NISO Z.39.19-2005 ‘Guidelines for the Construction, Format, and Management of Monolingual Controlled Vocabularies’ and includes terms derived from international valuation standards, such as European Valuation Standards (TEGoVA, 2012), International Valuation Standard (IVSC, 2013), Standard on Mass Appraisal of Real Property (IAAO, 2013a), Standard on Automated Valuation Models (2003), Standard on Ratio Studies (IAAO, 2013b). It is encoded through the Simple Knowledge Organization Systems (SKOS) specifications developed by World Wide Web Consortium (W3C) for standardized representation of structured vocabularies. The Valuation Thesaurus reveals the core semantic of the immovable property valuation domain, and therefore supports the identification of candidate classes, class attributes and relationships for the further elaboration of the mentioned LADM Valuation Module.@en

The aim of this research is to investigate the combined use of IndoorGML and the Land Administration Domain Model (LADM) to define the accessibility of the indoor spaces based on the ownership and/or the functional right for use. The users of the indoor spaces create a relationship with the space depending on the type of the building and the function of the spaces. The indoor spaces of each building have different usage functions and associated users. By defining the user types of the indoor spaces, LADM makes it possible to establish a relationship between the indoor spaces and the users. LADM assigns rights, restrictions, and responsibilities to each indoor space, which indicates the accessible spaces for each type of user. The three-dimensional (3D) geometry of the building will be impacted by assigning such functional rights, and will provide additional knowledge to path computation for an individual or a group of users. As a result, the navigation process will be more appropriate and simpler because the navigation path will avoid all of the non-accessible spaces based on the rights of the party. The combined use of IndoorGML and LADM covers a broad range of information classes: (indoor 3D) cell spaces, connectivity, spatial units/boundaries, (access/use) rights and restrictions, parties/persons/actors, and groups of them. The new specialized classes for individual students, individual staff members, groups of students, groups of staff members are able to represent cohorts of education programmes and the organizational structure (organogram: faculty, department, group). The model is capable to represent the access times to lecture rooms (based on education/teaching schedules), use rights of meeting rooms, opening hours of offices, etc. The two original standard models remain independent in our approach, we do not propose yet another model, but applications can fully benefit of the potential of the combined use, which is an important contribution of this paper. The main purpose of the combined use model is to support the indoor navigation, but could also support different applications, such as the maintenance and facility management work, by computing the cleaning cost based on the space floor area. The main contributions of this paper are: a solution for the combined use of IndoorGML-LADM model, a conceptual enhancement of LADM by the refinement of the LA_Party package with specialization for staff and student (groups), and the assessment of the model by converting sample data (from two complex university buildings) into the model, and conducting actual access-rights aware navigation, based on the populated model@en

The paper describes the ongoing developments and standardisation in land administration. Standards are relevant in relation to build as well as maintain and develop a land administration. Standards like the ISO 19152 Land Administration Domain Model (LADM) are helping to jump-start new initiatives and are connecting top-down and bottom-up projects together. The LADM facilitates the efficient set-up of land administration and can function as the core of any land administration system. LADM is flexible, widely applicable and functions as a central source of state-of-the-art international knowledge on this topic. Some future trends in the domain and the maintenance of the standard are presented and being discussed in the paper. These trends may be relevant for the development of a second edition of the LADM over the coming years. These models do not include land administration processes for initial data acquisition, data maintenance and data publication. This is because these processes were considered to be country-specific when the first edition of LADM was prepared; a generic and global approach was likely to be difficult to model. This view may now need reconsideration.@en

Immovable property valuation is performed by public sector actors for several land management activities, such as property taxation, expropriation or compulsory purchase of land, land re-adjustment and land consolidation; and private sector actors perform valuation for purchase, real estate financing, investment analysis, and further property transactions. The valuation process returns estimated value (e.g. market value) of property units based on their legal, physical, geographic, economic, and environmental characteristics, as recorded at public registries or observed on location. The ISO 19152:2012 Land Administration Domain Model (LADM) presents a conceptual schema for the specification of property units and their legal and geometric characteristics recorded at cadaster and land register, and relates these datasets with other property related datasets (e.g., valuation, taxation, land use, land cover) recorded at external databases. A recently initiated collaborative research (see Çağdaş, 2016) aims at developing a data model for one of these external databases, in terms of a Valuation Module for the ISO 19152:2012 LADM which is supposed to define semantics of valuation databases maintained by public authorities especially for immovable property taxation. The present paper presents preliminary results of this initiative, and describes a draft version of the Valuation Module which specifies the input and output data used and produced when single or mass appraisal processes are performed according to published standards and recommendations. It also presents a questionnaire which was prepared to create an inventory of valuation applications all over the world, and will be used as source data for the elaboration of the draft module. The paper also opens a discussion about this initiative, and calls for contributions of other relevant bodies (e.g. FIG, OGC, TEGOVA, IVSC and IAAO) for the further development of the draft Valuation Module.@en

As argued in many earlier FIG publications, the potential benefits of 3D Cadastre are huge. This is especially true in the Caribbean setting with quite dense urban areas and large and important marine areas, where rights (restrictions and responsibilities; RRRs) in 3D is a prerequisite for the blue economy. The Caribbean with a plethora of 3D use cases present, limited legacy data and systems, and a relative small size, is an excellent site for establishing an integrated 2D/3D Cadastral registration. Such a future system will support sustainable development of the Caribbean in the economic sense, while protecting the environmental values and human values (based on legislation and tools to support this). This paper will present an initial inventory of 11 different relevant 3D Cadastre use cases in the Caribbean (from Aruba, Bonaire and Trinidad&Tobago). This initial inventory gives an indication of the multi-disciplinary nature and importance of the topic, but will also be used for scoping the future development.@en

In this paper we investigate the possible synergy between two different but related standards: OGC’s IndoorGML and ISO TC211’s LADM. Both (can) deal with 3D spaces with properties, constraints and associations attached and both can operate with abstract notations of space. But there are also differences, e.g. LADM is a conceptual model, while IndoorGML is also an actual XML schema (technical model), which can be used directly for data exchange and storage. Also, the scope is different; e.g. IndoorGML focuses on indoor spaces, while LADM addresses all spaces (in principle a complete subdivision of the countries territory, including outdoor, water and surface spaces). LADM models legal and administrative concepts such as use and ownership rights of spaces related to certain parties. IndoorGML puts emphasis on connectivity of spaces related to the navigability as one of the main use cases. These characteristics make the two standards quite complementary and this motivates our exploration in the combination of both. The spaces defined by LADM are the results of legal/administrative rights, restrictions, responsibilities (largest possible homogeneous spaces with respect to these RRRs). The space subdivision of IndoorGML is based on navigable areas and their connectivity. IndoorGML also recognizes other spaces, called abstract spaces. The paper will compare the space characteristics of the two models and will explore options to combine the models.@en