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The Design and Implementation of a Cadastral Database with a Spatiotemporal Modeling Approach in Turkey
In this study, the requirements of a cadastral database were analyzed for Turkey and a spatiotemporal database was designed and developed to fulfill the requirements for spatial, temporal, and spatiotemporal queries for cadastral data. The study was implemented in Cayyolu Quarter of Cankaya District in Ankara, the capital city of Turkey. The cadastral data and the basic cadastral queries have certain spatial and temporal characteristics, such as querying the changes on the location and the shape of a land parcel, querying the ownership changes on a land parcel, etc. Therefore, a spatiotemporal database modeling technique was used to model the cadastral database. The system requirements were defined based on the land laws in Turkey and by interviewing the technical staff of TKGM. After collecting the system requirements, a conceptual database design was performed using the Spatiotemporal Entity-Relationship (STER) Model in combination with the Enhanced Entity Relationship (EER) model. The proposed conceptual schema was then mapped onto a logical data model in a relational design approach. Oracle 8i Spatial was chosen as DBMS because it provides spatial data handling capability. The physical design and database system implementation phases were treated together. The database tables defined in logical schema were created using Oracle 8i Spatial. The cadastre and land registry data of the study area were loaded into the database tables created. Since Oracle 8i does not provide graphic edit and display functions for spatial data MapInfo 6.0 GIS software was used to retrieve, display, manipulate, and analyze the cadastral data.
2. Cadastral Data The cadastre is an information system consisting of two parts: (i) a series of maps or plans showing the size and location of all land parcels, and (ii) the text records that describe the attributes of the land. The basic spatial unit of cadastre is a land parcel on which land tenure and land use records are compiled (figure 1).  Figure 1: A part of a cadastral map. In Turkey, TKGM is responsible for land registration and cadastre works. The main tasks of TKGM are to make cadastral survey, to make all registration operations and contracts on land rights, and to determine land tenure method. All cadastral data are produced by TKGM. Only a few types of data auxiliary to cadastral surveys, such as accurate geodetic control points, 1:25000-scale maps, forest maps, etc., are obtained from other government organizations. Basic categories of cadastral data produced by TKGM include the geodetic reference network, cadastral maps, land use information, and land tenure records. To efficiently design a cadastral database, the user needs were determined. The intended users of the database were identified and analyzed. To do that the technical staff of Cankaya Cadastre Office, Photogrammetry and Geodesy Department, and Cadastre Department of TKGM were interviewed. The Cadastre Law coded 3402, the regulations of TKGM, the regulations for large scale mapping, a few cadastre books, and other documentation, such as cadastral maps, parcel modification forms, title deed books, etc., were examined. Some of the examples for spatial, temporal, and spatiotemporal queries that can be invoked are as follows;
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