Nov. 1, 2019
Coordinated Cadastres and Coordinates as Evidence:
Dr. Michael Barry, Professor Department of Geomatics Engineering University of Calgary, Chair Land Tenure and Cadastral Systems, Director of FIG Foundation, explores this topic in his most recent publication.
Drawing on twenty years of practical surveying land surveying experience, the article examines the two main options for coordinated cadastres. It then provides some practical examples of how to handle coordinates as evidence and finally how to use evidence from digital cadastral databases. The first policy option is that coordinates as mathematical evidence constitute boundary corners. The second is that coordinates are merely evidence of the most probable position of a boundary corner. The latter option is the best as the former can result in anomalies, loss of land and a boundary system that floats around the landscape. The practical examples advocate an intuitive approach to using coordinates as evidence. In any spatial data analysis and modelling exercise, the solution that uses the fewest parameters is best. Likewise, one should not throw a similarity transformation at a cadastral survey problem without a critical inspection of the data and ascertaining how many parameters are actually relevant. Lastly, the article provide advice on how to use evidence from digital cadastral databases for boundary retracement and re-establishment surveys. Only coordinates of points that have been generated by survey should be adopted. Treat all others with caution.
For the full article on the Alberta Land Surveying Association website click here