A model for the creation and progressive improvement of a digital cadastral data base

A digital cadastral data base (DCDB) is a big investment for a jurisdiction tasked with the administration of land boundaries. In the past, the development of such a database produced no real pay-back on investment before many years of time, and millions of dollars in cash had been committed. The Land Administration Domain Model (LADM) (ISO-TC211, 2012) provides a schema in which the progressive creation and improvement of a DCDB is possible; to allowing benefits to be obtained even in the early stages of effort. It also incorporates the necessary structure to ensure that a useful historical record of the cadastre can be kept. This paper explores issues to be faced in the development of software based on the LADM, which retains the history of the cadastre, and allows for progressive improvement of the data. From experience gained in the development of cadastral databases of the Queensland (Australia) Department of Natural Resources and Mines, and the Netherlands Kadaster, a suggested logical schema is presented and discussed with respect to the requirements of a progressively developed and refined cadastral database. Rather than each cadastral jurisdiction developing its own database structure from basic geometric primitives, this paper proposes the establishment of a cadastral schema, based on the LADM, which can support all levels of encoding, variable accuracy and topological purity, while maintaining a comprehensive history. This would allow data quality to vary by geographic and temporal location and would be configurable to allow for country profiles under ISO 19152; thus permitting local terminology and language to be retained. Many jurisdictions are having extreme difficulty in successfully creating a cadastral database, so an open source type of software development may be indicated and desirable. This paper presents findings based on theoretical consideration and the construction of a proof of concept database, which indicate that such a schema is a practical proposition for the development of a digital cadastral data base.