Managing the dynamics of the New Zealand spatial cadastre

In 1995, the concept of a dynamic cadastre, based on a dynamic geodetic datum, was proposed for New Zealand to recognize that all cadastral boundaries in New Zealand are in some form of motion - relative to each other and relative to the geodetic datum which is also in motion. Subsequently New Zealand implemented a semi-dynamic geodetic datum which is accompanied by a deformation model. Later, a survey conversion project resulted in the boundaries of 70% of the land parcels in New Zealand being coordinated to survey accuracy in terms of the semi-dynamic datum. These boundaries continue to be adjusted by least squares as new cadastral survey observations and geodetic control stations are integrated into the network. However the deformation model has not, in practice, been routinely applied to cadastral boundaries. In 2010 and 2011, the Canterbury region in the South Island of New Zealand was subjected to a sequence of earthquakes that caused widespread damage and resulted in some boundaries being ruptured by up to 4 metres. A set of localized deformation models was developed to model the seismic movements. Propagating these movements through to all affected cadastral boundaries has proved to be a major undertaking which is described in this paper