A Database Implementation of LADM Valuation Information Model in Turkish Case Study

Abstract

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.