Refining the survey model of the LADM ISO 19152–2: Land registration

Cadastral surveying involves the delineation of property boundaries and the extent and documentation of easements and restrictions (imposed by private or public law), forming the foundation for Land Administration (LA). Survey models and processes constitute vital parts of Cadastres and Land Administration Systems (LASs). However, these models are often inadequately documented and lack standardization in practice. To address the global diversity and complexity of legal and administrative challenges in LA, standardization efforts have yielded the ISO 19152:2012 (ISO, 2012) Land Administration Domain Model (LADM), the Global Land Tool Network's (GLTN) Social Tenure Domain Model (STDM), and the OGC LandInfra/InfraGML standard. The current edition of the LADM focuses on standardised conceptual modelling of LA-related information, including a dedicated sub-package for Spatial and Surveying representation. As part of the ongoing LADM revision, a refined survey model is being developed to support a broad range of surveying and data acquisition approaches and levels of accuracy. Recognizing that surveying technology is not bound by national practices and regulations, this paper focuses specifically on the surveying aspect of LADM. It illustrates that the proposed refined survey model is applicable not only to conventional real property formation but also to participatory land rights recordation processes. The approach adopted in this research is technology-neutral, accommodating the ongoing evolution of surveying technology. It offers support for a broad range of surveying and data acquisition approaches, with varying levels of accuracy. As the demand for high-precision positioning has been persistent within the land mapping and surveying community, particularly since the initial adoption of GPS, aiming to achieve centimetre-level accuracies (initially confined to local services), the paper addresses the fundamental principles of the High Accuracy Service (HAS) concept within the proposed model. The main results presented in this paper are the conceptual model of the refined survey model of LADM Edition II (ISO19152–2), as well as an abstract, reference, cadastral surveying workflow following the principles of the proposed model

Initial Registration of 3D Parcels

Registering the rights of a 3D parcel provides certainty of ownership, protection of rights and unambiguous spatial location. While not all cadastral jurisdictions in the world maintain a digital cadastral database, the concepts of such registration hold true regardless of whether it is a paper-based cadastre or a digital one. Similarly, the motivations and purpose for the creation of a 2D cadastre for individual jurisdictions applies for 3D cadastres as well. It provides a security of ownership of 3D parcel, protects the rights of the owners, and provides valuable financial instruments such as mortgage, collateral, valuation and taxation. The current life cycle of the development of a land parcel includes processes beginning from outside the cadastral registration sphere, such as zoning plans and permits, but has a direct impact on how a certain development application is processed. Thus, in considering the changes required to allow a jurisdiction to register 3D, it is important to note the sphere of influence that could have an impact on 3D registration. These include planners, notaries, surveyors, data managers and registrars; however for the purpose of this paper, the research is focused on the core 3D aspects that are institutional, legal and technical. This paper explores approaches and solutions towards the implementation of initial 3D cadastral registration, as derive by current procedures of registration of 3D parcels in various countries worldwide. To this purpose, the paper analyses the categorisations and approaches to 3D spatial units and examines the validation requirements (constraints) on a cadastral database, at various levels of maturity. In this view, 3D data storage and visualization issues are examined in relation to the level of complexity of various jurisdictions, as provided by the results of the country inventory combined with a worldwide survey in 2010 and updated in 2014 (Van Oosterom, et al, 2014). It seems that significant progress has been achieved in providing legal provisions for the registration of 3D cadastres in many countries and several have started to show 3D information on cadastral plans such as isometric views, vertical profiles or text environment to facilitate such data capture and registration. Moreover, as jurisdictions progress towards an implementation of 3D cadastres, much 3D data collected in other areas (BIM, IFC CityGML files, IndoorGML, InfraGML and LandXML) open up the possibility of creating 3D cadastral database combining the existing datasets. The usability, compatibility and portability of these datasets is a low cost solution to one of the costliest phases of the implementation of 3D cadastres, which is the initial 3D data capture

Research and Development Progress in 3D Cadastral Systems

The content of this Special Issue has its origin at the “5th International FIG Workshop on 3DCadastres”, organized in Athens, Greece, 18–20 October 2016. The Workshop provided a further stepping stone to identifying key issues and challenges within 3D Cadastres developments, as well as exchanging ideas and solutions between scientists from academia, industry, and government. After the workshop, authors of selected papers (or in some cases, two teams of authors of related papers) were invited to publish in this Special Issue, which is devoted to the legal, organizational, and technical aspects of 3D Cadastres. Therefore, this Special Issue is where practice and research meet, influence, stimulate, and support each other, showing the progress in the key areas of 3D Cadastres, including the legal framework of 3D Cadastres, initial registration of 3D parcels, 3D data management, visualization, distribution, and delivery of 3D parcels. The 13 papers published in this Special Issue are the end result of the authors’ hard work and a rigorous journal’s peer review process. We would like to thank the authors for their valuable contributions and of course express thanks to the IJGI Editorial Office and the reviewers for their thoughtful suggestions and constructive criticism. Even though all papers in this Special Issue stand on their own, depending on cultural, geographical, and technical differences, we have tried to produce a rather holistic approach, covering this field of research. Moreover, we have highlighted similarities and dissimilarities in addressing important 3D Cadastral topics, as follows.Printed Edition of the Special Issue Published in International Journal of Geo-Information, ISBN 978-3-03921-056-5 (Pbk); ISBN 978-3-03921-057-2 (PDF)GIS Technologi

Addressing Public Law Restrictions within a 3D Cadastral Context

Public law affects contemporary life by imposing various regulations that apply in 3D space. However, such restrictions are either literally described in legal documents or presented on a horizontal plane, resulting in ambiguities, especially in the case of vertically overlapping restrictions with a significant impact on land management. This paper investigates public law restrictions (PLR) applying to 3D space and their management within a 3D cadastral context. Within this framework, a case study is examined in Greece concerning the establishment of a subway station, focusing on public utilities, archaeological legislation, and building regulations. Relative legal documentation is compiled and mapped in a 3D PLR model, presenting inefficiencies and malfunctions that can be resolved if PLRs are addressed within a 3D cadastral context. Stipulations implying restrictions in 3D space within current legislation are presented, along with the restrictions deriving from the absolute character of ownership right, thus highlighting the significance of 3D definition, modeling and recording of PLRs

Research and Development Progress in 3D Cadastral Systems

The increasing complexity of infrastructures and densely built-up areas requires a proper registration of the legal status (private and public), which can only be provided to a limited extent by the existing 2D cadastral registrations. The registration of the legal status in complex 3D situations is investigated under the header of 3D Cadastres. This publication, containing 13 selected contributions on 3D Cadastre, addresses the following areas