The modelling of spatial units (parcels) in the land administration domain model (LADM)

The Land Administration Domain Model (LADM) is under development within the Technical Committee 211 (TC211) of the International Organisation for Standardization (ISO) and identified as ISO 19152. Within the LADM classical cadastral concepts as “parcel” and “boundary” have been extended to be able to include spatial representations of overlapping tenures or claims and also multidimensional objects (3D and 2D/3D, combined with temporal dimensions). Furthermore, a series of new representations are possible apart from topologically well structured parcels (here called spatial units). Text based, sketch based, point based, line-based, polygon based, or topological based representations of spatial units are possible. The topological spatial units are defined by a consistent topological structure(with no gaps, overlaps or intersections), which is in contrast with a set of polygons, where a consistent topological structure is not guaranteed. A line-based spatial unit is represented by a collection of lines which may be collected from different sources or surveys. A point-based spatial unit contains only the coordinates of the unit’s reference point. A text based spatial unit is not represented by coordinates, but has a spatial unit description in words, e.g. the metes and bounds system (a spatial unit description in terms of distance, direction, and landmarks). All these spatial units may have a 3D representation, and a provision is made for a mixture of 2D and 3D spatial units to co-exist. A level is a collection of spatial units with a geometric or thematic coherence. The concept of level is related to the notion of “legal independence” from ‘Cadastre 2014’. This allows for the flexible introduction of spatial data from different sources and accuracies, including utility networks, buildings and other 3D spatial units, such as mining claims, or construction works. The paper explores the LADM spatial component, which is further based on ISO standards, combined with new concepts as “boundary face string” and partially unbounded primitives. Spatial profiles and the different spatial representations are used to demonstrate the flexibility of spatial representations of this domain model; for formal and non formal land administrations systems alike. The first trial implementation of the Queensland (Australia)Digital Cadastral Database (DCDB) for 2D parcel encoding using the line-based spatial profile will be discussed in detail, together with the polygon based spatial profile for the spatial units of the Portuguese land administration

The Final Steps Towards an International Standard for Land Administration The Final Steps Towards an International Standard for Land Administration

This paper presents an overview of the last (sometimes minor) modifications from DIS to FDIS. Most modifications are improvements to increase the flexibility of the LADM, e.g. the relationships between rights and arbitrary sets of spatial units (parcels). Consequently, with more flexibility, the notion of conformance testing has been adjusted. Also, the ever increasing adoption of the LADM is illustrated via a number of new country profiles. This clearly shows the need, and practically, the growing support for the LADM over the past years (in addition to the ever growing number of positive votes for the LADM within ISO)

Ontology - based integration of topographic data sets

The integration of topographic data sets is defined as the process of establishing relationships between corresponding object instances in different, autonomously produced, topographic data sets of the same geographic space. The problem of integrating topographic data sets is in finding these relationships, considering the differences in content and abstraction. A conceptual framework is developed. Components of this framework are ontologies and sets of surveying rules. New in this approach is the introduction of a reference model. A reference model belongs uniquely to the combination of topographic data sets to be integrated. The framework is tested on two topographic data sets with area instances (polygons) which have crisp and complete boundaries and are not displaced for cartographic reasons. The overall conclusion is that the ontology-based framework is feasible, if (1) there is (at least partial) knowledge of the surveying rules, and (2) the data sets can be synchronized in time. The application of this framework is most suitable for object classes with instances that are easy to identify and have a limited spatial extent (e.g., buildings). (c) 2005 Elsevier B.V. All rights reserved

To the Memory of My Father

2 bibliography make

Investigating the conformity between the land administration domain model and the Vietnamese land administration system

LADM is the conceptual schema on cadastre which is derived from Core Cadastral Domain Model. It was submitted to the International Organization for Standardization (ISO) with a desire to design and develop land administration systems (LAS) more efficiently and effectively. It is important that, if Vietnam wants to apply LADM to its LAS, the conformity between this system and LADM need to be investigated. In this paper, the similarities and differences about goals, concepts and some classes between LADM and the Vietnamese LAS are described. In Vietnam, land by law is belonging to all people with the State acting as the representative owner. It means that the citizens only have user rights on land, and therefore are qualified as "land user", but not "land owner". However, land users can have ownership on immovable properties associated with land. Therefore, there is a clear separation between rights on the land parcel and properties associated with it. Another important issue is to determine the source of land use. Depending on types of land use source, rights, responsibilities, restrictions or financial obligations shall be different. Thus, an issue is raised as how to present these characteristics in the model. Based on a literature review about LADM, understanding Vietnamese LAS, and analysis of users’ requirements, it can be seen that the adoption of LADM in Vietnam is possible. By the comparison in terms of what LADM classes can be applied directly, and what LADM classes have to be modified to be suitable in Vietnam LAS, this paper shows the country profile for the Vietnamese LAS. Some new classes are added in the model as DC_ParcelSource, DC_Forest, and DC_PerennialsGarden. DC_ParcelSource is a subclass of DC_Source which is the description of land use source for each land parcel. DC_Forest and DC_PerennialsGarden are subclasses of DC_SpatialUnit. These results contribute to more complete land administration model in Vietnam based on LADM and to lay foundation of modernization of Vietnamese LAS

Ontology-based geographic data set integration

In order to develop a system to propagate updates we investigate the semantic and spatial relationships between independently produced geographic data sets of the same region (data set integration). The goal of this system is to reduce operator intervention in update operations between corresponding (semantically similar) geographic object instances. Crucial for this reduction is certainty about the semantic similarity of different object representations. In this paper we explore a framework for ontology-based geographic data set integration, an ontology being a collection of shared concepts. Components of this formal approach are an ontology for topographic mapping (a domain ontology), an ontology for every geographic data set involved (the application ontologies), and abstraction rules (or capture criteria). Abstraction rules define at the class level the relationships between domain ontology and application ontology. Using these relationships, it is possible to locate semantic similarity at the object instance level with methods from computational geometry (like overlay operations). The components of the framework are formalized in the Prolog language, illustrated with a fictitious example, and tested on a practical example