Measurement-based multipurpose cadastral systems.

摘要

Multipurpose cadastral systems are required by local governments to improve land-conveyance procedures, furnish a basis for equitable taxation, and provide information for resource management and environmental planning. Several problems inherent in present coordinate-based implementations, however, slow the rate of introduction of multipurpose cadastral systems in many potential local governments. This thesis investigates multipurpose cadastral systems that are based on measurements.; The fundamental concepts of measurement-based multipurpose cadastral systems are that measurements are first class objects and are the primary carriers of metric information. Coordinate values that are required to answer metric queries are computed from the stored measurements as needed. Coordinate computations by local least squares adjustments consider measurements around the neighborhood of query areas only. To update a system with new measurements only requires the addition of the measurements to the database. The information on the quality of measurements available in a measurement-based system is useful when assessment about the reliability of measurements and derived metric values must be made. Preserving original measurements as opposed to calculated coordinates is the foundation for building a legally supported multipurpose cadastral system.; The investigation reveals that measurement-based concepts can serve as the foundation for a cadastral system. An implementation can start without prior establishment of a network of control points. Existing cadastral measurements are used as a basis of a system. With precise instruments available to surveyors, good quality measurements from standard daily operations are added to the system without extra cost. Control measurements are integrated into the system the same way as cadastral measurements. The addition of measurements increases the accuracy of the system over time.; An implementation of a measurement-based system is feasible in a very near future with the rapid development of computers. The hardware issues are resolved: the storage of redundant measurements is no longer a problem because storage media like hard disk are now affordable. Various database management software allows easy management of measurements. The processing speed of workstations in the mid 1990's will permit local adjustments to be performed of the order of seconds.