Article Preview
Top1. Introduction
Land has specific role in various aspects of human life such as economic, social and legal. Accordingly, Food and Agricultural Organization (FAO) introduces land as one of the most important capitals of men in any society (Kalantari, 2008). In legal aspect, land is a volume of space from centre of earth to infinite sky that contains different rights such as ownership rights and land use rights. Therefore, in order to perform better land management, registration of these rights in cadastre system is a major issue. Current cadastre system divides land to 2D parcels and registers certain legal rights for any parcel. In addition to registration of land rights, presentation of these rights is a major issue because “in some situations, legal rights are tightly attached to the physical object like an apartment or underground construction which makes the visualization indispensable” (Wang et al, 2012, p. 6). Although 2D cadastre can register the rights and restriction related to land, it has several limitations for representing these rights. Some of these limitations are:
- •
Representation of multiple ownership rights for a 2D parcel (Fiqure1.a)
- •
Representation of interference in the land rights (Fiqure1.b)
- •
Representation of rights of easement
- •
Representation of rights of superficies
- •
Representation of rights for underground buildings and urban infrastructures (Figure 1.c)
- •
Representation of several independent land use for a parcel (Fiqure1.d)
- •
…
Figure 1. Some limitation of 2D cadastre
These limitations find more significance by urban growth and rapid developments of multilevel structural constructions above and below land parcels. 3D cadastre by considering elevation for parcels can overcome these limitations (Stoter, 2004). “3D cadastre is a discrete division of 3D urban geospace, and many urban features, such as buildings, parks, tunnels/metro, underground constructions and overcrossing buildings are the 3D cadastral entities” (Ying et al, 2012, p.4). Using 3D geometry and 3D topology, land rights are transferred from 2D space to 3D space. In different analyses, for example in subway’s route designing, we need to 3D cadastre data. In fact, in the new generation of cadastre systems, the vertical boundaries for parcels are defined along the horizontal boundaries and 2D maps are replaced by 3D representation. Visualization of 3D cadastre allows graphical means to communicate complexity of overlapping situations and helps users to spatially comprehend such situations.
Another important issue related to cadastre is access to geometrical data. Cadastre by registration of land rights is known as a main data source in land information management. Different organizations such as tax, legal, judicial, disaster management organizations and municipality require land information. Most important government uses of 3D cadastre are their management and decision making support. For example, in planning and disaster management applications, online access and visualization of 3D cadastral data are often effective (Aditya, 2011). 3D representation of parcels and buildings needs to be visualized on top of the terrain and flood hazard map of the area as a 3D view. 3D visualization provides convincing perspectives for community and decision makers in the flood disaster responses (Aditya, 2011). In addition to this, municipalities often favour the management and application of a 3D cadastral system in urban space to plan and make decisions for future urban space and future land use. Nevertheless, access to cadastre information faces some limitations such as: