Property valuation is a process that promotes sustainable development as it supports and forms several land management activities. Access to information on the legal, geometric, physical, locational and environmental characteristics of property units together with the economic indicators are required for an effective property valuation system. Traditional cadastral systems generally provide only two-dimensional (2D) legal and geometric information about property units, however, today's valuation practices would benefit significantly from three-dimensional (3D) information in order better to estimate and explain values of property units. The purpose of this paper is to examine how 3D spatial datasets and spatial analyses have been used in property valuation, and to develop 3D valuation unit profile(s) in line with the examination results for the recently proposed Valuation Information Model that extends the ISO 19152:2012 Land Administration Domain Model (LADM) from the valuation point of view. The study focuses more on 3D locational and environmental characteristics of property units; particularly visibility and especially viewshed analysis in terms of property valuation. By using open topography, building and height datasets of the Netherlands, a number of viewshed analyses are conducted to show how it can be utilized using different 3D data sources. The main contribution of the article is to present how 3D datasets and spatial analyses could be used to support property valuation activities and to investigate to what extent it is possible and meaningful to include derived 3D characteristics of property units in valuation registries.

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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

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

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

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

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

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

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