entities and relations that characterize national laws and regulations regarding the
rights, restrictions and responsibilities that accompany land ownership. The refine-
for this and allows for some integration. However, this still implies fragmentation
of development effort especially for supporting software. Each country will also
software code (such as data entry and management forms). These schema and
processes will vary due to differences in language, culture, common practice, laws
and legal definitions etc. Hence, it is unlikely that a single data model can unify all
the possible variations, or that a single software package can provide all of the
43
Initial research investigating cross-jurisdictional schema variation has shown
that this problem can be addressed with the implementation of a process or
“event” model (as opposed to a simplified structural or “state” model which re-
quires re-engineering each time it is applied in a new and potentially different con-
text). Data schema may also vary due to evolving requirements which become
more sophisticated as the land administration infrastructure becomes more ma-
ture. This temporal schema evolution is considered conceptually similar in nature
to cross- jurisdictional schema variation. Solutions that are coded based on what is
known at the time will be difficult and costly (in terms of the maturity of develop-
er resources in developing nations) to modify. Importantly, it is expected that
these systems will require more modification over time than systems developed in
economically advanced nations where infrastructure is more mature, well-under-
stood and less prone to change. Hence, it is essential to consider the dynamic
evolution of schema so that the effort required to evolve a mature land records
management system is reduced.
The building blocks of the OSCAR project consider both of these types of vari-
ation in the hope of providing a solution that can evolve between countries (and
therefore provide a foundation for a FLOSS community to develop) and over time
(without major development effort) as each nation matures in it’s use of the com-
mon functions programmed into the generic code base. The proposed solution
also address issues of data integration (which would be difficult if each country de-
veloped its own schema independently) and the lack of human resources by not
necessarily requiring fundamental code to be (re-)developed by each jurisdiction.
Rather, it is expected that functions can be built within and around the conceptual
model outlined by Hay and Hall (2009). In essence, this approach conceives of an
“instrument” which signifies a legal change associated with the status of a land
parcel through a formal registration and land surveying process. Instruments link
Agents (people such as surveyors and conveyancers), organizations (such as banks
and government departments), groups (such as land developers and companies)
to Objects (a Register Object such as a parcel of land, an apportionment of a par-
cel, or a building that exists on a parcel or a unit within an apportionment) via
Events which implement the temporal aspects of land administration. Together in-
struments, agents, objects and events form workflows (or business processes) and
capturing the relations between instruments and documents (such as titles, cadas-
tral parcel boundaries, survey plans etc.) as they move through the land adminis-
tration process is the foundation of the OSCAR approach.
Recent research in the area of semantic markup and ontology for the cadastral
domain argues for the use of semantic web technologies especially in the area of
data integration (for both applying updates and cross-jurisdictional data sharing).
This also highlights the inflexibility of the structural or relational model for both
domain and temporal modeling (Spéry et al., 2001; Schuurman and Leszczynski,
44
2006). Process and temporal aspects of the domain noted above are also the sub-
ject of recent research with specific importance placed on the concurrent defini-
tion of spatial data (in this case parcel boundaries and their physical and title-
based attributes) and associated process models (van der Molen, 2002; Albrecht et
al., 2008). In addressing these issues, the architecture proposed for OSCAR exter-
nalizes the domain terms and concepts in the form of a domain ontology made up
of resources that describe and link concepts and terms within the domain. The
Resource Description Framework (RDF)
28
is used to detail the associations and re-
lationships between data items and their types. This, together with the use of a
process or event based architecture, allows a highly dynamic data model to be
used and results in the conceptually straightforward database design and develop-
ment approach described at a high level by Hay and Hall (2009).
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