P5 Presentation by Pieter Soffers
Main mentor: Prof. dr. ir. P.J.M. van Oosterom
Second mentor: ir. E. Verbree
Co-reader: Dr. S. Zlatanova
For nearly 200 years the Netherlands’ Cadastre, Land Registry and Mapping Agency – in short ‘Kadaster’ has been the organization that registers and maintains all legal rights concerning property in the Netherlands. An elementary part of its activities is the spatial description of parcels that are built up by boundaries which are surveyed in the field and depicted on the Dutch cadastral map. Nowadays this is an open source digital map which provides an overview of the cadastral situation for the entire country. The map exists of unique representations of all cadastral boundaries and parcels. It must be pointed out though that these locations are only depicted by approximation, which is caused by several factors. The most precise location of a boundary still remains the original survey data in the field, which is documented on separate survey documents. In the Dutch cadastral map every parcel has its own number, which is the link to original survey documents. Relating the boundary on the map to the correct survey data happens by intuition. This is feasible when cadastral situations are documented from scratch. However the Dutch cadastral situation is dynamic; parcels can split and merge, which results in new numbers and extra survey documents. As a result searching for survey data is getting more and more complex. Additionally the Kadaster has used different survey techniques over time offering different meta data, administration and accuracy. The survey data have been stored at different locations. Also boundary reconstructions lead to extra survey documents for one boundary. All these factors together have decreased the interaction and overview of quality.
This thesis presents a research to design a data model which relates all survey data directly to its boundaries in the Dutch cadastral map instead of parcel numbers. As a starting point for this data model requirements are defined, which are based on preliminary investigation of the Dutch cadastral work flow. The requirements are establishing a link between survey data and the Dutch cadastral map, incorporating all survey methods, assuming more elements in the Dutch cadastral map as entities in their own right, the maintenance of topology, the maintenance of quality and the use of ISO standards.
The design of the data model uses the Land Administration Domain Model (LADM) as template. This is an international standard for land administration. This data model was adjusted to the situation of the Kadaster. This is a common method applied by cadastral organizations to improve their work flow. The LADM template offers solutions for generally upcoming cadastral issues as well as a data organization that is clearer and more accessible for externals. Nevertheless there are multiple approaches to solve the issues of the Kadaster by this template. This research will discuss several options to meet the stated requirements and deliberate on the best choice. Real Dutch cadastral cases are used to demonstrate how the final data model operates. At last a comparison is made with related cadastral systems abroad to reflect on its drawbacks and benefits.
The final model can support the current work flow of the Kadaster by assuming boundaries as own entities. A direct link to its related survey data saves time, labour and expert knowledge. The model places similar objects in similar classes in order to increase overview. The data model may be a starting point for improvement of the Dutch cadastral map.