Temporal Perspective Towards the Design of Cadastral Database in Taiwan

Regardless of whether explicitly recorded, every geographic data has various aspects about time. Especially for integrated applications, the temporal aspects of geographic data from different stakeholders play an extremely critical role. Ignorance of the temporal difference or valid time of the datasets may easily lead to unexpected and even unpredictable mistakes. It is hence the responsibility for data designers to cautiously consider the demanded temporal information during schema design and correctly convey unambiguous meanings of the temporal information to users. It is also the responsibility of users to correctly interpret the temporal information before making any decision. Cadastre is governments’ system developed to facilitate the management of lands and buildings, so as to protect citizens’ property and drive the growth of economy. The massive volume of real estate transactions makes the management of cadaster systems a big challenge that involves both spatial and temporal aspects. From the interoperable application perspective, the ultimate goal of the cadastre system is to ensure every piece of information is based on the precise and coherent spatio-temporal modeling results, such that every decision can be made without ambiguity. It is therefore necessary to have a thorough examination on the spatio-temporal characteristics of the various types of cadastral data, as well as their relationships with the cadastre operations. This research mainly focuses on the temporal modelling issue, especially in the valid time and semantics of temporal information. The Land Administration Domain Model (LADM) from ISO/TC211 (International Organization for Standardization/ Technical Committee 211) is chosen as the reference model in this study because it offers a whole package of standardized classes specifically designed for land administration purpose. As LADM is endorsed by international organizations like FIG and already adopted by many countries for developing national profiles for their cadastre systems, we believe the research results are not only beneficial to the digital cadastre systems of Taiwan, but also contribute to the guidelines for designing temporal information for domain data. Thie preliminary result shows the feasibility of introducing LADM to model the various temporal characteristics for the current cadastral data in Taiwan, but additional guidelines for designing temporal information with semantics to fulfill the needs required by related laws are also necessary. It would be even advantageous such standardized vocabularies can be unambiguously defined and extensively used in cross-domain integrated applications to improve the interoperability of temporal information