3D cadastres for densely occupied informal situations: Necessity and possibility

Abstract Much of 3D cadastre research and development targets high valued urban land, including condominiums, apartment buildings, and office complexes. The value of the land and the economic activity generated from transactions in this urban space potentially support the cost and time spent on establishing and maintaining a 3D cadastre. Methods for data acquisition and for construction and maintenance of the 3D cadastre are also simpler in the regular and formally planned and surveyed structures of the high value urban environment. Low-income, urban areas of informal tenure and informal development, however, also need and can benefit from a land administration system supported by a 3D cadastre but are neglected in the 3D cadastre research. Mechanisms are required for quick and cost effective construction of a 3D cadastre in this type of area to support land management and regularisation procedures, and to provide security of tenure. Light Detection and Ranging (LiDAR) is one technology that may be examined to differentiate structures in densely occupied environments where limited information and limited resources must be able to be used for managing the land and also protecting informal rights. This paper initially posits the need for 3D cadastres in low-income but densely structured urban settlements. It then tests the ability of an existing LiDAR dataset together with orthoimagery, derived to be low cost so therefore having limited specifications, for capturing sufficient definition of 3D occupation in the low-income, densely structured case study area of Laventille in Trinidad and Tobago. The difficulties of manually or automatically discriminating between close and overlapping structures and boundaries are highlighted and it is found that there is still a need for adjudication and verification of boundaries on the ground, even when physical features can be discerned from the software.