APPLICATION OF ITERATIVE WEIGHTED SIMILARITY TRANSFORMATION (IWST) DEFORMATION DETECTION METHOD USING COORDINATE DIFFERENCES FROM DIFFERENT OBSERVATIONAL CAMPAIGNS

Omogunloye O.G.l.*, Ipadeola A.O.**, Shittu O.G.* and Ojegbile B.M.*

*Department of Surveying and Geoinformatics Engineering

**Department of Surveying and Geoinformatics

Faculty of Engineering, University of Lagos, Akoka-Lagos, Nigeria

Faculty of Environmental Sciences, University of Ilorin, Ilorin, Nigeria

E-mail:- gabolushohan@yahoo.com, dapsen2010@gmail.com

ABSTRACT

In this study, application of deformation in geodesy is presented. Deformation analysis is one of the major researchfields in geodesy and geomatics. This involves detecting and analysing change in shape and form of objects and structures on the earth surface using geodetic techniques. Deformation analysis process comprises measurement and analysis phases. Measurements can be collected using several techniques. The measurement techniques and the instruments used for such monitoring are categorized as geodetic and non-geodetic (i.e., geotechnical/structural) methods. A geodetic method was utilized in this study. 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 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. The deformation and statistical analyses shows that of the 18 stations analysed, five (5) have been significantly deformed while the remaining thirteen (13) stations are relatively stable over time.