The Survey Uncertainty of Existing Boundaries

Blackburn, Ben (2018) The Survey Uncertainty of Existing Boundaries. [USQ Project]


The boundary parcels that form the basis of the cadastre in Queensland can be compared to a puzzle of which the dimensions of each piece has been built with varying levels of precision – the pieces do not fit perfectly. Over time, boundaries have been established with measuring equipment with different accuracy capabilities. In Queensland, and elsewhere around the world, technological advances and other factors are a driving force to modernise to a survey-accurate cadastre. Compiling a survey-accurate cadastre is a significant undertaking, which requires an understanding of the survey uncertainty (SU) of the existing boundaries to assess any adjustments made. This dissertation aimed to model SU estimates as an aid to simplify analysing the accuracy of existing boundaries. The model would interpolate a general SU value for a survey plan on the basis of the time period in which it was created, as the capabilities of measuring technology can be categorised to time periods. However, modelling SU of boundaries also requires consideration of other factors such as the method of traversing and geometry of a boundary. Thus least-squares analysis of these factors was conducted utilising Starnet to investigate the behaviour of these effects. A secondary objective – to research and test methods of estimating line uncertainty appropriate for boundaries was derived from the premise that current techniques for estimating SU in surveying are vertex based, however judgements are frequently made on the spatial relationship between boundary lines and an item of interest. Methodology for this objective was to test 2 techniques identified in Geographic Information System (GIS) literature; Monte-Carlo simulation and an analytical method. The key results of the first objective were that the method of traversing has minimal effect on SU estimates - when traversing is reasonably close to the boundary. Variance in angle geometry of a boundary was found to have a negligible effect on SU estimates. The number of lines in a boundary has an effect on SU, however could not be isolated from the effect of distances. When variances in distances of a boundary parcel became larger, modelling the correlation between SU and distance became difficult and unreliable, leading to the conclusion that SU estimates could not be generalised by the proposed curve-fitting techniques. With regards to the second objective, results of simulation and analytical procedures were generally in agreement with existing literature, however comprehensive testing was unable to be implemented to validate previous work. It was concluded that the analytical procedure was easier to implement and produce results. Although objectives were not successful, this dissertation provided an insight into the complexities of developing a survey-accurate cadastre and identified a method for surveyors to convey uncertainty of the spatial location of a boundary line.

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Item Type: USQ Project
Item Status: Live Archive
Faculty/School / Institute/Centre: Historic - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying (1 Jul 2013 - 31 Dec 2021)
Supervisors: Campbell, Glenn
Qualification: Bachelor of Surveying (Honours) (Surveying)
Date Deposited: 05 Sep 2022 05:51
Last Modified: 27 Jun 2023 04:47
Uncontrolled Keywords: survey-accurate cadastre; boundaries

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