APPLICATION OF ITERATIVE SIMILARITY TRANSFORMATION (IWST) DEFORMATION DETECTION METHOD USING COORDINATE DIFFERENCES FROM DIFFERENT OBSERVATIONAL CAMPAIGNS IN LAGOS, NIGERIA
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Date
2016-03
Journal Title
Journal ISSN
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Publisher
NIGERIAN INSTITUTION OF SURVEYORS
Abstract
In this study, application of deformation in geodesy is presented. This paper presents a deformation analysis of control network with a focus on procedure that consists of network design, network adjustment of individual campaigns, trend analysis and deformation detection of the displacement field. The Iterative Weighted Similarity Transformation (IWST) robust method of analysis has been adopted and applied in determining the trend of movements and deformation detection for all the common points in the network. The developed procedure has been implemented in a program package developed using MATLAB software. Two campaign sets of data of control stations within Lagos State, Nigeria were used. The coordinate changes in the point positions were investigated. Results from the analysis indicate that all the stations have undergone movements but not all are significantly deformed. Results from the deformation and statistical analyses indicate that all the points have undergone movements but not all are significant. At 95% significance level chosen for the Fisher’s distribution (F) (i.e., PT<F(0.05,2,df), the single point displacement (PT) test indicates out of the 18 stations investigated, 13 are relatively stable and 5 are unstable and have undergone significant deformation over time.
Description
Useful for Deformation Studies
Keywords
DEFORMATION, ANALYSIS, COORDINATE, ADJUSTMENT, IWST METHOD