A Legal Cadastral Domain Model
During the last decade numerous attempts have been made to describe and discuss the cadastral domain on both national and international level. In this paper the term “legal cadastral domain” is used as a common term for laws and regulations regulating the content of traditional cadastre, multipurpose cadastre and land register storing legal real property information, regardless of any national differentiation between these registers. A problem towards description of the domain is that real property and cadastre are not homogeneous and standardised terms and different definitions are presented by several authors, see e.g. (FIG, 1995); (Kaufman and Steudler, 1998); (Silva and Stubkjaer, 2002). Such standardisation efforts are in addition primarily orientated towards technical storage environment of cadastre and other (software) solutions, but have, in my opinion, minor focus on legal aspects, even if the importance of the legal cadastral domain has been addressed by several authors, e.g. (Lemmen et al, 2003) and (Kaufman and Steudler, 1998). So, surprisingly little has been done to describe the legal issues of standardisation of real property information and cadastre.
Further progress in the development of the core cadastral domain model
SUMMARY In our paper ‘Impact Analysis of Recent Geo-ICT Developments on Cadastral Systems’ presented at the FIG Washington Congress in April 2002 we concluded that cadastral systems must be flexible and generic because user requirements keep on changing due to new legislation, new registrations, new technology. In addition we stated that (geo-) ICT developments, such as geo-DBMSs, Internet, GPS, and data exchange (XML) and modeling standards (UML), have greatly contributed towards the efficient implementation of effective systems. However, a core cadastral domain model supported by vendor software would have increased efficiency yet more. Such a model would enable application of Model Driven Architectures in the context of cadastral systems.
An Object-Oriented, Formal Approach to the Design of Cadastral Systems
Modeling GIS or applications of GIS with object-oriented tools is difficult for the practitioners. In this case study the deed registration system is studied using formal, object-oriented tools. The formal modeling approach also shows the differences and the similarities in the deed registration system used in the USA and the property registration system in Europe. A formal modeling approach will demonstrate the functional similarities, caused by the similar social demands, and the differences owing to different historic developments. It is found that the models are comparable and the rules are fundamentally similar. The checks for a valid transfer of ownership are quite similar, but the time of checking is different. A Continental title registration system checks documents when they are received, whereas the US registers first without checking and only later the validity is checked by a prospective buyer’s lawyer. Several results can be generalized to other administrative GIS applications: • The question of identity plays a primary role and several types of LGHQWLWLHV may be hierarchically nested. • Administrative rules are less strict than database logic on what constitutes an entity or an identifier (the XQLTXH QDPH DVVXPSWLRQ is maintained only within a context). • Administrative time for a registry is a simple ordered scale. These results are of practical importance for the design of GIS software which includes a ODQG RZQHUVKLS OD\HU and should be applicable in countries with different property registration systems. It shows the designers of property registration software what can be built into a general, widely usable system and when adaptation to local rules is necessary. The study was motivated by efforts to design a property registration system for a reform country in Eastern Europe. In this situation, one has to understand how social demands and legal rules relate to the technical solution. To start with a formal model is the best way to achieve this.