Miran Ferlan

Transition from 2D to 3D real property cadastre: The case of the Slovenian cadastre

Abstract The land administration system, providing a mechanism to support the management of real properties, is one of the most crucial infrastructures of any country. This infrastructure is needed to support planning and implementation of land-related policies, and in general to support human decisions and activities in our environment. The fundamental part of a modern land administration system is the land cadastre. Over the last decade, the demand for three-dimensional (3D) cadastre has increased significantly worldwide. The physical and legal complexities of the built and natural environment prompt new concepts and definitions of real property units in order to meet the demands of a todays society and to balance private and public spatial interests. Particularly in urban areas, including other areas with intensive human interventions into space, there is a tendency to use space above and below the Earths surface, above and below structures, etc. Complex 3D objects cannot be defined and registered as cadastral objects in the traditional 2D land cadastre and represented in a 2D cadastral map. For this purpose, next to the land cadastre, in 2000, Slovenia introduced the building cadastre. From the juridical point of view, the current cadastral system is not sufficient for all 3D situations. In this paper, we discuss upgrade possibilities of data models of the land cadastre and building cadastre to introduce a unique 3D real property cadastre in Slovenia. We believe that the data available in the current cadastres will significantly contribute toward the 3D real property cadastre and 3D graphical representation of cadastral data; nevertheless, some additional data are needed. The minimum data required could be provided already through the current cadastral procedures.

Accurate area determination in the cadaster: case study of Slovenia

ABSTRACT This paper discusses methodological problems of accurate area determination in the cadaster. The paper contrasts the ambiguous legal definition of the parcel boundary and parcel area in relation to the theoretically well-defined geodetic parcel boundary and the geodetic parcel area on the reference ellipsoid. To align with the real world, parcel area must account for terrain elevation. Various approximate methods for area determination which can be used in the cadaster are tested. A highly accurate method for parcel area computation is proposed, based on an equal-area projection. Considering the geodetic parcel area as a reference, the achievable accuracy of different methods is evaluated. For this analysis, the coordinates of the parcel boundary points are treated as error-free. Finally, the relevance of various systematic errors is discussed in relation to the statistical uncertainty of the parcel area, which could be gained by an a real-time kinematic GNSS survey. A case study is presented for the territory of Slovenia, its georeferencing rules, land demarcation pattern, and characteristics of its topography. Based on the results of this study, some general recommendations for the parcel area determination are given.